Performance information

• The deficiency of methylglyoxal synthase promotes cell proliferation in Synechocystis sp. PCC 6803 under mixotrophic conditions　　　　　　　　　　　　　　　
  Aikeranmu Kadeer; Yuuma Ishikawa; Kaushalya Dayarathne; Atsuko Miyagi; Toshiki Ishikawa; Masatoshi Yamaguchi; Maki Kawai-Yamada
  Plant Biotechnology, Volume：41, Number：4, First page：393, Last page：399, Dec. 2024, [Reviewed]
  English, Scientific journal
  DOI：https://doi.org/10.5511/plantbiotechnology.24.0718a
  DOI ID：10.5511/plantbiotechnology.24.0718a
• Production of extracellular superoxide contributes to photosynthesis via elimination of reducing power and regeneration of NADP+ in the red-tide-forming raphidophyte Chattonella marina complex　　　　　　　　　　　　　　　
  Koki Yuasa; Takayoshi Ichikawa; Yuma Ishikawa; Haruhiko Jimbo; Maki Kawai-Yamada; Tomoyuki Shikata; Yoshitaka Nishiyama
  Harmful Algae, Volume：139, First page：102712, Last page：102712, Nov. 2024, [Reviewed]
  Elsevier BV, Scientific journal
  DOI：https://doi.org/10.1016/j.hal.2024.102712
  DOI ID：10.1016/j.hal.2024.102712, ISSN：1568-9883
• Arabidopsis DREB26/ERF12 and its close relatives regulate cuticular wax biosynthesis under drought stress condition
  Kaoru Urano; Yoshimi Oshima; Toshiki Ishikawa; Takuma Kajino; Shingo Sakamoto; Mayuko Sato; Kiminori Toyooka; Miki Fujita; Maki Kawai‐Yamada; Teruaki Taji; Kyonoshin Maruyama; Kazuko Yamaguchi‐Shinozaki; Kazuo Shinozaki
  The Plant Journal, Volume：120, Number：5, First page：2057, Last page：2075, Oct. 2024, [Reviewed]
  SUMMARY
  
  Land plants have evolved a hydrophobic cuticle on the surface of aerial organs as an adaptation to ensure survival in terrestrial environments. Cuticle is mainly composed of lipids, namely cutin and intracuticular wax, with epicuticular wax deposited on plant surface. The composition and permeability of cuticle have a large influence on its ability to protect plants against drought stress. However, the regulatory mechanisms underlying cuticular wax biosynthesis in response to drought stress have not been fully elucidated. Here, we identified three AP2/ERF transcription factors (DREB26/ERF12, ERF13 and ERF14) involved in the regulation of water permeability of the plant surface. Transmission electron microscopy revealed thicker cuticle on the leaves of DREB26‐overexpressing (DREB26OX) plants, and thinner cuticle on the leaves of transgenic plants expressing SRDX repression domain‐fused DREB26 (DREB26SR). Genes involved in cuticular wax formation were upregulated in DREB26OX and downregulated in DREB26SR. The levels of very‐long chain (VLC) alkanes, which are a major wax component, increased in DREB26OX leaves and decreased in DREB26SR leaves. Under dehydration stress, water loss was reduced in DREB26OX and increased in DREB26SR. The erf12/13/14 triple mutant showed delayed growth, decreased leaf water content, and reduced drought‐inducible VLC alkane accumulation. Taken together, our results indicate that the DREB26/ERF12 and its closed family members, ERF13 and ERF14, play an important role in cuticular wax biosynthesis in response to drought stress. The complex transcriptional cascade involved in the regulation of cuticular wax biosynthesis under drought stress conditions is discussed.
  Wiley, Scientific journal
  DOI：https://doi.org/10.1111/tpj.17100
  DOI ID：10.1111/tpj.17100, ISSN：0960-7412, eISSN：1365-313X
• The effect of light availability and light wavelength on growth, 2-MIB biosynthesis, and 2-MIB-related gene expression in Pseudanabaena foetida var. intermedia.　　　　　　　　　　　　　　　
  Kaushalya Dayarathne; Toshiki Ishikawa; Aikeranmu Kadeer; Masatoshi Yamaguchi; Maki Kawai-Yamada
  Archives of microbiology, Volume：206, Number：9, First page：367, Last page：367, Aug. 2024, [Reviewed], ［International magazine］
  2-methylisoborneol (2-MIB) is an odiferous metabolite mainly produced by cyanobacteria, contributing to taste and odor problems in drinking water. The mechanisms involved in 2-MIB biosynthesis in cyanobacteria are not yet completely understood. This study investigated the effect of light availability and wavelength on growth, 2-MIB synthesis, and related gene expression in Pseudanabaena foetida var. intermedia. A significantly lower 2-MIB production was observed in P. foetida var. intermedia during the dark period of a 12-h photoperiod. Exposure to green light resulted in a significant decrease in 2-MIB production compared to white light and red light. The relative expression levels of 2-MIB-related genes in P. foetida var. intermedia were significantly lower during the dark period of a 12-h photoperiod and when cultured under green light. The expression of 2-MIB-related genes in cyanobacteria appears to be light-dependent. This study suggests that the demand for photopigment synthesis under unfavorable light conditions affects the 2-MIB synthesis in cyanobacteria.
  English, Scientific journal
  DOI：https://doi.org/10.1007/s00203-024-04099-w
  DOI ID：10.1007/s00203-024-04099-w, PubMed ID：39105810
• Metabolic diversity analysis and genome wide assessment of oxalate accumulation in the leaves of rice Oryza sativa cultivars
  Atsuko Miyagi; Nobuhiro Tanaka; Matthew Shenton; Kaworu Ebana; Satoshi Ohkubo; Shunsuke Adachi; Taiichiro Ookawa; Maki Kawai-Yamada
  Plant Biotechnology, Volume：41, First page：1, Last page：7, Mar. 2024, [Reviewed]
  Japanese Society for Plant Cell and Molecular Biology, Scientific journal
  DOI：https://doi.org/10.5511/plantbiotechnology.23.1025a
  DOI ID：10.5511/plantbiotechnology.23.1025a, ISSN：1342-4580, eISSN：1347-6114
• Adjustment of light-responsive NADP dynamics in chloroplasts by stromal pH
  Yusuke Fukuda; Chinami Ishiyama; Maki Kawai-Yamada; Shin-nosuke Hashida
  Nature Communications, Volume：14, Number：1, Nov. 2023, [Reviewed]
  Abstract
  
  Cyclic electron transfer (CET) predominates when NADP⁺ is at basal levels, early in photosynthetic induction; however, the mechanism underlying the subsequent supply of NADP⁺ to fully drive steady-state linear electron transfer remains unclear. Here, we investigated whether CET is involved in de novo NADP⁺ supply in Arabidopsis thaliana and measured chloroplastic NADP dynamics to evaluate responsiveness to variable light, photochemical inhibitors, darkness, and CET activity. The sum of oxidized and reduced forms shows that levels of NADP and NAD increase and decrease, respectively, in response to light; levels of NADP and NAD decrease and increase in the dark, respectively. Moreover, consistent with the pH change in the stroma, the pH preference of chloroplast NAD⁺ phosphorylation and NADP⁺ dephosphorylation is alkaline and weakly acidic, respectively. Furthermore, CET is correlated with upregulation of light-responsive NADP level increases and downregulation of dark-responsive NADP level reductions. These findings are consistent with CET helping to regulate NADP pool size via stromal pH regulation under fluctuating light conditions.
  Springer Science and Business Media LLC, Scientific journal
  DOI：https://doi.org/10.1038/s41467-023-42995-9
  DOI ID：10.1038/s41467-023-42995-9, eISSN：2041-1723, ORCID：146070222
• MHP1 and MHL generate odd-chain fatty acids from 2-hydroxy fatty acids in sphingolipids and are related to immunity in Arabidopsis thaliana　　　　　　　　　　　　　　　
  Marina Ushio; Toshiki Ishikawa; Takakazu Matsuura; Izumi C. Mori; Maki Kawai-Yamada; Yoichiro Fukao; Minoru Nagano
  Plant Science, Volume：336, First page：111840, Last page：111840, Nov. 2023, [Reviewed]
  Elsevier BV, Scientific journal
  DOI：https://doi.org/10.1016/j.plantsci.2023.111840
  DOI ID：10.1016/j.plantsci.2023.111840, ISSN：0168-9452
• Heterologous expression of mtf and mtc genes of Pseudanabaena foetida var. intermedia is sufficient to produce 2-methylisoborneol in Escherichia coli.　　　　　　　　　　　　　　　
  Kaushalya Dayarathne; Toshiki Ishikawa; Satoru Watanabe; Yuuma Ishikawa; Kadeer Aikeranmu; Hina Kitagawaa; Natsumi Komatsubara; Masatoshi Yamaguchi; Maki Kawai-Yamada
  Microbiology spectrum, Volume：11, Number：5, First page：e0256123, Sep. 2023, [Reviewed], ［International magazine］
  Microbial volatile metabolite 2-methylisoborneol (2-MIB) causes odor and taste issues in drinking water, making it unappealing for human consumption. It has been suggested that 2-MIB biosynthesis consists of two main steps, namely, methylation of geranyl diphosphate into 2-methyl geranyl diphosphate by geranyl diphosphate methyl transferase (GPPMT) and subsequent cyclization into 2-MIB by 2-MIB synthase (MIBS). Pseudanabaena foetida var. intermedia is a 2-MIB-producing cyanobacterium whose GPPMT and MIBS enzymes are encoded by adjacent mtf and mtc genes. The present study identified a 2-MIB-related gene cluster composed of cnbA, mtf, mtc, and cnbB genes in P. foetida var. intermedia. The two homologous cyclic nucleotide-binding protein genes, cnbA and cnbB, were detected adjacent to the mtf and mtc genes, respectively. The nucleotide sequence of the cnbA-mtf-mtc-cnbB gene cluster showed 99.55% identity with 2-MIB synthesis-associated gene cluster of Pseudanabaena sp. dqh15. RT-PCR results revealed that mtf and mtc genes are co-expressed, while cnbA and cnbB genes are expressed independently in P. foetida var. intermedia. To investigate whether only mtf and mtc genes are sufficient for 2-MIB synthesis, the two-gene unit (mtf-mtc) was introduced into Escherichia coli strain JM109 via overexpression vector pYS1C. Gas chromatograph-mass spectrometry results showed that the E. coli strain transformed with mtf-mtc was able to produce 2-MIB. The intracellular 2-MIB level in P. foetida var. intermedia was higher than the extracellular 2-MIB level, while the transformed E. coli strain showed an opposite trend. Growth inhibition was observed in the 2-MIB-producing transformed E. coli strain. IMPORTANCE Contamination of drinking water with odiferous microbial metabolite 2-MIB is a worldwide concern. Removal of 2-MIB from drinking water burdens the water purification process. Therefore, it is important to search for alternative methods, such as suppressing the production of 2-MIB by aquatic microorganisms. For that, it is necessary to expand the current knowledge about the mechanism of 2-MIB synthesis at the genetic level. This study revealed that mtf and mtc genes of the 2-MIB-related gene cluster are transcribed as a single unit in P. foetida var. intermedia, and the expression of both mtf and mtc genes is essential and sufficient for 2-MIB synthesis in E. coli heterologous gene expression system.
  English, Scientific journal
  DOI：https://doi.org/10.1128/spectrum.02561-23
  DOI ID：10.1128/spectrum.02561-23, PubMed ID：37732762, PubMed Central ID：PMC10580876
• NAC domain transcription factors VNI2 and ATAF2 form protein complexes and regulate leaf senescence.　　　　　　　　　　　　　　　
  Isura Sumeda Priyadarshana Nagahage; Kohei Matsuda; Kyoko Miyashita; Sumire Fujiwara; Chanaka Mannapperuma; Takuya Yamada; Shingo Sakamoto; Toshiki Ishikawa; Minoru Nagano; Misato Ohtani; Ko Kato; Hirofumi Uchimiya; Nobutaka Mitsuda; Maki Kawai-Yamada; Taku Demura; Masatoshi Yamaguchi
  Plant direct, Volume：7, Number：9, First page：e529, Sep. 2023, [Reviewed], ［International magazine］
  The NAM, ATAF1/2, and CUC2 (NAC) domain transcription factor VND-INTERACTING2 (VNI2) negatively regulates xylem vessel formation by interacting with another NAC domain transcription factor, VASCULAR-RELATED NAC-DOMAIN7 (VND7), a master regulator of xylem vessel formation. Here, we screened interacting proteins with VNI2 using yeast two-hybrid assay and isolated two NAC domain transcription factors, Arabidopsis thaliana ACTIVATION FACTOR 2 (ATAF2) and NAC DOMAIN CONTAINING PROTEIN 102 (ANAC102). A transient gene expression assay showed that ATAF2 upregulates the expression of genes involved in leaf senescence, and VNI2 effectively inhibits the transcriptional activation activity of ATAF2. vni2 mutants accelerate leaf senescence, whereas ataf2 mutants delay leaf senescence. In addition, the accelerated leaf senescence phenotype of the vni2 mutant is recovered by simultaneous mutation of ATAF2. Our findings strongly suggest that VNI2 interacts with and inhibits ATAF2, resulting in negatively regulating leaf senescence.
  English, Scientific journal
  DOI：https://doi.org/10.1002/pld3.529
  DOI ID：10.1002/pld3.529, PubMed ID：37731912, PubMed Central ID：PMC10507225
• Metabolic changes associated with dark-induced leaf senescence in Arabidopsis nadk2 mutants　　　　　　　　　　　　　　　
  Chaomurilege; Atsuko Miyagi; Toshiki Ishikawa; Masatoshi Yamaguchi; Hideki Murayama; Maki Kawai-Yamada
  Plant Signaling and Behavior, Volume：18, Number：1, First page：e2215618, May 2023, [Reviewed], ［International magazine］
  English, Scientific journal
  DOI：https://doi.org/10.1080/15592324.2023.2215618
  DOI ID：10.1080/15592324.2023.2215618
• Chloroplastic Sec14-like proteins modulate growth and phosphate deficiency responses in Arabidopsis and rice
  Mailun Yang; Yasuhito Sakruaba; Toshiki Ishikawa; Namie Ohtsuki; Maki Kawai-Yamada; Shuichi Yanagisawa
  Plant Physiology, Apr. 2023, [Reviewed]
  Abstract
  
  Phosphorus is an essential nutrient acquired from soil as phosphate (Pi), and its deficiency severely reduces plant growth and crop yield. Here, we show that single nucleotide polymorphisms (SNPs) at the PHOSPHATIDYLINOSITOL TRANSFER PROTEIN7 (AtPITP7) locus, which encodes a chloroplastic Sec14-like protein, are associated with genetic diversity regarding Pi uptake activity in Arabidopsis (Arabidopsis thaliana). Inactivation of AtPITP7 and its rice (Oryza sativa) homolog (OsPITP6) through T-DNA insertion and CRISPR/Cas9-mediated gene editing, respectively, decreased Pi uptake and plant growth, regardless of Pi availability. By contrast, overexpression of AtPITP7 and OsPITP6 enhanced Pi uptake and plant growth, especially under limited Pi supply. Importantly, overexpression of OsPITP6 increased the tiller number and grain yield in rice. Targeted metabolome analysis of glycerolipids in leaves and chloroplasts revealed that inactivation of OsPITP6 alters phospholipid contents, independent of Pi availability, diminishing the reduction in phospholipid content and increase in glycolipid content induced by Pi deficiency; meanwhile, overexpression of OsPITP6 enhanced Pi deficiency-induced metabolic alterations. Together with transcriptome analysis of ospitp6 rice plants and phenotypic analysis of grafted Arabidopsis chimeras, these results suggest that chloroplastic Sec14-like proteins play an essential role in growth modulations in response to changes in Pi availability, although their function is critical for plant growth under any Pi condition. The superior traits of OsPITP6-overexpressing rice plants also highlight the potential of OsPITP6 and its homologs in other crops as additional tools for improving Pi uptake and plant growth in low Pi environments.
  Oxford University Press (OUP), Scientific journal
  DOI：https://doi.org/10.1093/plphys/kiad212
  DOI ID：10.1093/plphys/kiad212, ISSN：0032-0889, eISSN：1532-2548
• Loss of peroxisomal NAD kinase 3 (NADK3) affects photorespiration metabolism in Arabidopsis　　　　　　　　　　　　　　　
  Shota Suzuki; Daimu Tanaka; Atsuko Miyagi; Kentaro Takahara; Masaru Kono; Chaomurilege; Ko Noguchi; Toshiki Ishikawa; Minoru Nagano; Masatoshi Yamaguchi; Maki Kawai-Yamada
  Journal of Plant Physiology, Volume：283, First page：153950, Mar. 2023, [Reviewed], ［International magazine］
  English, Scientific journal
  DOI：https://doi.org/10.1016/j.jplph.2023.153950
  DOI ID：10.1016/j.jplph.2023.153950
• Dynamic seasonal changes in photosynthesis systems in leaves of Asarum tamaense, an evergreen understorey herbaceous species　　　　　　　　　　　　　　　
  Naoki Wada; Issei Kondo; Ryouichi Tanaka; Junko Kishimoto; Atsuko Miyagi; Maki Kawai-Yamada; Yusuke Mizokami; Ko Noguchi
  Annals of Botany, Volume：in press, Dec. 2022, [Reviewed], ［International magazine］
  English, Scientific journal
  DOI：https://doi.org/10.1093/aob/mcac156
  DOI ID：10.1093/aob/mcac156
• Arabidopsis nitrate-induced aspartate oxidase gene expression is necessary to maintain metabolic balance under nitrogen nutrient fluctuation
  Moriaki Saito; Mineko Konishi; Atsuko Miyagi; Yasuhito Sakuraba; Maki Kawai-Yamada; Shuichi Yanagisawa
  Communications Biology, Volume：5, Number：1, Dec. 2022, [Reviewed]
  Abstract
  
  Nitrate is a nutrient signal that regulates growth and development through NLP transcription factors in plants. Here we identify the L-aspartate oxidase gene (AO) necessary for de novo NAD⁺ biosynthesis as an NLP target in Arabidopsis. We investigated the physiological significance of nitrate-induced AO expression by expressing AO under the control of the mutant AO promoter lacking the NLP-binding site in the ao mutant. Despite morphological changes and severe reductions in fresh weight, the loss of nitrate-induced AO expression resulted in minimum effects on NAD(H) and NADP(H) contents, suggesting compensation of decreased de novo NAD⁺ biosynthesis by reducing the growth rate. Furthermore, metabolite profiling and transcriptome analysis revealed that the loss of nitrate-induced AO expression causes pronounced impacts on contents of TCA cycle- and urea cycle-related metabolites, gene expression profile, and their modifications in response to changes in the nitrogen nutrient condition. These results suggest that proper maintenance of metabolic balance requires the coordinated regulation of multiple metabolic pathways by NLP-mediated nitrate signaling in plants.
  Springer Science and Business Media LLC, Scientific journal
  DOI：https://doi.org/10.1038/s42003-022-03399-5
  DOI ID：10.1038/s42003-022-03399-5, eISSN：2399-3642
• Metabolomic analysis of rice brittle culm mutants reveals each mutant- specific metabolic pattern in each organ
  Atsuko Miyagi; Kazuhisa Mori; Toshiki Ishikawa; Satoshi Ohkubo; Shunsuke Adachi; Masatoshi Yamaguchi; Taiichiro Ookawa; Toshihisa Kotake; Maki Kawai-Yamada
  Metabolomics, Volume：18, Number：12, Nov. 2022, [Reviewed]
  Springer Science and Business Media LLC, Scientific journal
  DOI：https://doi.org/10.1007/s11306-022-01958-9
  DOI ID：10.1007/s11306-022-01958-9, eISSN：1573-3890
• Loss of chloroplast-localized NAD kinase causes ROS stress in Arabidopsis thaliana　　　　　　　　　　　　　　　
  Chaomurilege; Yanhui Zu; Atsuko Miyagi; Shin-Nosuke Hashida; Toshiki Ishikawa; Masatoshi Yamaguchi; Maki Kawai-Yamada
  Journal of Plant Research, Volume：in press, Nov. 2022, [Reviewed], ［International magazine］
  English, Scientific journal
  DOI：https://doi.org/10.1007/s10265-022-01420-w
  DOI ID：10.1007/s10265-022-01420-w
• Sphingolipids with 2-hydroxy fatty acids aid in plasma membrane nanodomain organization and oxidative burst
  Tomomi Ukawa; Fumihiko Banno; Toshiki Ishikawa; Kota Kasahara; Yuuta Nishina; Rika Inoue; Keigo Tsujii; Masatoshi Yamaguchi; Takuya Takahashi; Yoichiro Fukao; Maki Kawai-Yamada; Minoru Nagano
  Plant Physiology, Volume：189, Number：2, First page：839, Last page：857, Jun. 2022, [Reviewed]
  Abstract
  
  Plant sphingolipids mostly possess 2-hydroxy fatty acids (HFA), the synthesis of which is catalyzed by FA 2-hydroxylases (FAHs). In Arabidopsis (Arabidopsis thaliana), two FAHs (FAH1 and FAH2) have been identified. However, the functions of FAHs and sphingolipids with HFAs (2-hydroxy sphingolipids) are still unknown because of the lack of Arabidopsis lines with the complete deletion of FAH1. In this study, we generated a FAH1 mutant (fah1c) using CRISPR/Cas9-based genome editing. Sphingolipid analysis of fah1c, fah2, and fah1cfah2 mutants revealed that FAH1 hydroxylates very long-chain FAs (VLCFAs), whereas the substrates of FAH2 are VLCFAs and palmitic acid. However, 2-hydroxy sphingolipids are not completely lost in the fah1cfah2 double mutant, suggesting the existence of other enzymes catalyzing the hydroxylation of sphingolipid FAs. Plasma membrane (PM) analysis and molecular dynamics simulations revealed that hydroxyl groups of sphingolipid acyl chains play a crucial role in the organization of nanodomains, which are nanoscale liquid-ordered domains mainly formed by sphingolipids and sterols in the PM, through hydrogen bonds. In the PM of the fah1cfah2 mutant, the expression levels of 26.7% of the proteins, including defense-related proteins such as the pattern recognition receptors (PRRs) brassinosteroid insensitive 1-associated receptor kinase 1 and chitin elicitor receptor kinase 1, NADPH oxidase respiratory burst oxidase homolog D (RBOHD), and heterotrimeric G proteins, were lower than that in the wild-type. In addition, reactive oxygen species (ROS) burst was suppressed in the fah1cfah2 mutant after treatment with the pathogen-associated molecular patterns flg22 and chitin. These results indicated that 2-hydroxy sphingolipids are necessary for the organization of PM nanodomains and ROS burst through RBOHD and PRRs during pattern-triggered immunity.
  Oxford University Press (OUP), Scientific journal
  DOI：https://doi.org/10.1093/plphys/kiac134
  DOI ID：10.1093/plphys/kiac134, ISSN：0032-0889, eISSN：1532-2548
• VNI2 effectively inhibits transcriptional activities of VND7 through a conserved sequence　　　　　　　　　　　　　　　
  Aili Ailizati; Isura Sumeda Priyadarshana Nagahage; Atsuko Miyagi; Toshiki Ishikawa; Maki Kawai-Yamada; Taku Demura; Masatoshi Yamaguchi
  Plant Biotechnology, Volume：39, Number：2, First page：147, Last page：153, Jun. 2022, [Reviewed], ［Internationally co-authored］
  English, Scientific journal
  DOI：https://doi.org/10.5511/plantbiotechnology.22.0122a
  DOI ID：10.5511/plantbiotechnology.22.0122a
• Intraspecific interaction of host plants leads to concentrated distribution of a specialist herbivore through metabolic alterations in the leaves.
  Haruna Ohsaki; Atsuko Miyagi; Maki Kawai-Yamada; Akira Yamawo
  Functional Ecology, Volume：36, Number：3, First page：779, Last page：793, Mar. 2022, [Reviewed]
  Wiley, English, Scientific journal
  DOI：https://doi.org/10.1111/1365-2435.13988
  DOI ID：10.1111/1365-2435.13988, ISSN：0269-8463, eISSN：1365-2435
• An Arabidopsis NAC domain transcriptional activator VND7 negatively regulates VNI2 expression　　　　　　　　　　　　　　　
  Aili Ailizati; Isura Sumeda Priyadarshana Nagahage; Atsuko Miyagi; Toshiki Ishikawa; Maki Kawai-Yamada; Taku Demura; Masatoshi Yamaguchi
  Plant Biotechnology, Volume：38, Number：4, First page：415, Last page：420, Dec. 2021, [Reviewed], ［Internationally co-authored］
  English, Scientific journal
  DOI：https://doi.org/10.5511/plantbiotechnology.21.1013a
  DOI ID：10.5511/plantbiotechnology.21.1013a
• Change in expression levels of NAD kinase-encoding genes in Flaveria species　　　　　　　　　　　　　　　
  Masami Tanaka; Yuuma Ishikawa; Sayaka Suzuki; Takako Ogawa; Yukimi Y. Taniguchi; Atsuko Miyagi; Toshiki Ishikawa; Masatoshi Yamaguchi; Yuri N. Munekage; Maki Kawai-Yamada
  Journal of Plant Physiology, Volume：265, First page：153495, Last page：153495, Oct. 2021
  Elsevier BV, Scientific journal
  DOI：https://doi.org/10.1016/j.jplph.2021.153495
  DOI ID：10.1016/j.jplph.2021.153495, ISSN：0176-1617
• The NAD Kinase Slr0400 Functions as a Growth Repressor in Synechocystis sp. PCC 6803　　　　　　　　　　　　　　　
  Yuuma Ishikawa; Cedric Cassan; Aikeranmu Kadeer; Koki Yuasa; Nozomu Sato; Kintake  Sonoike; Yasuko Kaneko; Atsuko Miyagi; Hiroko Takahashi; Toshiki Ishikawa; Masatoshi Yamaguchi; Yoshitaka Nishiyama; Yukako Hihara; Yves Gibon; Maki Kawai-Yamada
  Plant and Cell Physiology, Volume：62, Number：4, First page：668, Last page：677, Sep. 2021, [Reviewed]
  
  NADP+, the phosphorylated form of nicotinamide adenine dinucleotide (NAD), plays an essential role in many cellular processes. NAD kinase (NADK), which is conserved in all living organisms, catalyzes the phosphorylation of NAD+ to NADP+. However, the physiological role of phosphorylation of NAD+ to NADP+ in the cyanobacterium Synechocystis remains unclear. In this study, we report that slr0400, an NADK-encoding gene in Synechocystis, functions as a growth repressor under light-activated heterotrophic growth conditions and light and dark cycle conditions in the presence of glucose. We show, via characterization of NAD(P)(H) content and enzyme activity, that NAD+ accumulation in slr0400-deficient mutant results in the unsuppressed activity of glycolysis and tricarboxylic acid (TCA) cycle enzymes. In determining whether Slr0400 functions as a typical NADK, we found that constitutive expression of slr0400 in an Arabidopsis nadk2-mutant background complements the pale-green phenotype. Moreover, to determine the physiological background behind the growth advantage of mutants lacking slr04000, we investigated the photobleaching phenotype of slr0400-deficient mutant under high-light conditions. Photosynthetic analysis found in the slr0400-deficient mutant resulted from malfunctions in the Photosystem II (PSII) photosynthetic machinery. Overall, our results suggest that NADP(H)/NAD(H) maintenance by slr0400 plays a significant role in modulating glycolysis and the TCA cycle to repress the growth rate and maintain the photosynthetic capacity.
  Oxford University Press (OUP), Scientific journal
  DOI：https://doi.org/10.1093/pcp/pcab023
  DOI ID：10.1093/pcp/pcab023, ISSN：0032-0781, eISSN：1471-9053, PubMed ID：33210985, PubMed Central ID：PMC7781788
• Reprogramming sphingolipid glycosylation is required for endosymbiont persistence in Medicago truncatula　　　　　　　　　　　　　　　
  William M. Moore; Candace Chan; Toshiki Ishikawa; Emilie A. Rennie; Heidi M.-L. Wipf; Veronica Benites; Maki Kawai-Yamada; Jenny C. Mortimer; Henrik V. Scheller
  Current Biology, Volume：31, Number：11, First page：2374, Last page：2385.e4, Jun. 2021
  Plant endosymbiosis relies on the development of specialized membranes that encapsulate the endosymbiont and facilitate nutrient exchange. However, the identity and function of lipids within these membrane interfaces is largely unknown. Here, we identify GLUCOSAMINE INOSITOL PHOSPHORYLCERAMIDE TRANSFERASE1 (GINT1) as a sphingolipid glycosyltransferase highly expressed in Medicago truncatula root nodules and roots colonized by arbuscular mycorrhizal (AM) fungi and further demonstrate that this enzyme functions in the synthesis of N-acetyl-glucosamine-decorated glycosyl inositol phosphoryl ceramides (GIPCs) in planta. MtGINT1 expression was developmentally regulated in symbiotic tissues associated with the development of symbiosome and periarbuscular membranes. RNAi silencing of MtGINT1 did not affect overall root growth but strongly impaired nodulation and AM symbiosis, resulting in the senescence of symbiosomes and arbuscules. Our results indicate that, although M. truncatula root sphingolipidome predominantly consists of hexose-decorated GIPCs, local reprogramming of GIPC glycosylation by MtGINT1 is required for the persistence of endosymbionts within the plant cell.
  Cell Press, English, Scientific journal
  DOI：https://doi.org/10.1016/j.cub.2021.03.067
  DOI ID：10.1016/j.cub.2021.03.067, ISSN：1879-0445, PubMed ID：33857428, SCOPUS ID：85104939324
• The Arabidopsis thaliana nucleotide sugar transporter GONST2 is a functional homolog of GONST1.　　　　　　　　　　　　　　　
  Beibei Jing; Toshiki Ishikawa; Nicole Soltis; Noriko Inada; Yan Liang; Gosia Murawska; Lin Fang; Fekadu Andeberhan; Ramana Pidatala; Xiaolan Yu; Edward Baidoo; Maki Kawai-Yamada; Dominique Loque; Daniel J Kliebenstein; Paul Dupree; Jenny C Mortimer
  Plant direct, Volume：5, Number：3, First page：e00309, Mar. 2021, ［International magazine］
  Glycosylinositolphosphorylceramides (GIPCs) are the predominant lipid in the outer leaflet of the plasma membrane. Characterized GIPC glycosylation mutants have severe or lethal plant phenotypes. However, the function of the glycosylation is unclear. Previously, we characterized Arabidopsis thaliana GONST1 and showed that it was a nucleotide sugar transporter which provides GDP-mannose for GIPC glycosylation. gonst1 has a severe growth phenotype, as well as a constitutive defense response. Here, we characterize a mutant in GONST1's closest homolog, GONST2. The gonst2-1 allele has a minor change to GIPC headgroup glycosylation. Like other reported GIPC glycosylation mutants, gonst1-1gonst2-1 has reduced cellulose, a cell wall polymer that is synthesized at the plasma membrane. The gonst2-1 allele has increased resistance to a biotrophic pathogen Golovinomyces orontii but not the necrotrophic pathogen Botrytis cinerea. Expression of GONST2 under the GONST1 promoter can rescue the gonst1 phenotype, indicating that GONST2 has a similar function to GONST1 in providing GDP-D-Man for GIPC mannosylation.
  English, Scientific journal
  DOI：https://doi.org/10.1002/pld3.309
  DOI ID：10.1002/pld3.309, PubMed ID：33763627, PubMed Central ID：PMC7980081
• The NAD kinase Slr0400 functions as a growth repressor in Synechocystis sp. PCC 6803.　　　　　　　　　　　　　　　
  Yuuma Ishikawa; Cedric Cassan; Aikeranmu Kadeer; Koki Yuasa; Nozomu Sato; Kintake Sonoike; Yasuko Kaneko; Atsuko Miyagi; Hiroko Takahashi; Toshiki Ishikawa; Masatoshi Yamaguchi; Yoshitaka Nishiyama; Yukako Hihara; Yves Gibon; Maki Kawai-Yamada
  Plant & cell physiology, Feb. 2021, ［Domestic magazine］
  NADP+, the phosphorylated form of nicotinamide adenine dinucleotide (NAD), plays an essential role in many cellular processes. NAD kinase (NADK), which is conserved in all living organisms, catalyzes the phosphorylation of NAD+ to NADP+. However, the physiological role of phosphorylation of NAD+ to NADP+ in the cyanobacterium Synechocystis remains unclear. In this study, we report that slr0400, an NADK-encoding gene in Synechocystis, functions as a growth repressor under light-activated heterotrophic growth conditions and light and dark cycle conditions in the presence of glucose. We show, via characterization of NAD(P)(H) content and enzyme activity, that NAD+ accumulation in slr0400-deficient mutant results in unsuppressed activity of glycolysis and tricarboxylic acid (TCA) cycle enzymes. In determining whether Slr0400 functions as a typical NADK, we found that constitutive expression of slr0400 in an Arabidopsis nadk2-mutant background complements the pale-green phenotype. Moreover, to determine the physiological background behind the growth advantage of mutants lacking slr04000, we investigated the photobleaching phenotype of slr0400-deficient mutant under high-light conditions. Photosynthetic analysis found in the slr0400-deficient mutant resulted from malfunctions in the PSII photosynthetic machinery. Overall, our results suggest that NADP(H)/NAD(H) maintenance by slr0400 plays a significant role in modulating glycolysis and the TCA cycle to repress the growth rate and maintain photosynthetic capacity.
  English, Scientific journal
  DOI：https://doi.org/10.1093/pcp/pcab023
  DOI ID：10.1093/pcp/pcab023, PubMed ID：33560438
• Redox regulation of NADP-malate dehydrogenase is vital for land plants under fluctuating light environment.　　　　　　　　　　　　　　　
  Yuichi Yokochi; Keisuke Yoshida; Florian Hahn; Atsuko Miyagi; Ken-Ichi Wakabayashi; Maki Kawai-Yamada; Andreas P M Weber; Toru Hisabori
  Proceedings of the National Academy of Sciences of the United States of America, Volume：118, Number：6, Feb. 2021, ［International magazine］
  Many enzymes involved in photosynthesis possess highly conserved cysteine residues that serve as redox switches in chloroplasts. These redox switches function to activate or deactivate enzymes during light-dark transitions and have the function of fine-tuning their activities according to the intensity of light. Accordingly, many studies on chloroplast redox regulation have been conducted under the hypothesis that "fine regulation of the activities of these enzymes is crucial for efficient photosynthesis." However, the impact of the regulatory system on plant metabolism is still unclear. To test this hypothesis, we here studied the impact of the ablation of a redox switch in chloroplast NADP-malate dehydrogenase (MDH). By genome editing, we generated a mutant plant whose MDH lacks one of its redox switches and is active even in dark conditions. Although NADPH consumption by MDH in the dark is expected to be harmful to plant growth, the mutant line did not show any phenotypic differences under standard long-day conditions. In contrast, the mutant line showed severe growth retardation under short-day or fluctuating light conditions. These results indicate that thiol-switch redox regulation of MDH activity is crucial for maintaining NADPH homeostasis in chloroplasts under these conditions.
  English, Scientific journal
  DOI：https://doi.org/10.1073/pnas.2016903118
  DOI ID：10.1073/pnas.2016903118, PubMed ID：33531363
• Ceramides mediate positional signals in Arabidopsis thaliana protoderm differentiation
  Kenji Nagata; Toshiki Ishikawa; Maki Kawai-Yamada; Taku Takahashi; Mitsutomo Abe
  Development, Volume：148, Number：2, First page：dev194969, Last page：dev194969, Jan. 2021
  The differentiation of distinct cell types in appropriate patterns is a fundamental process in the development of multicellular organisms. In Arabidopsis thaliana, protoderm/epidermis differentiates as a single cell layer at the outermost position. However, little is known about the molecular nature of the positional signals that achieve correct epidermal cell differentiation. Here, we propose that very-long-chain fatty acid-containing ceramides (VLCFA-Cers) mediate positional signals by stimulating the function of ARABIDOPSIS THALIANA MERISTEM LAYER1 (ATML1), a master regulator of protoderm/epidermis differentiation, during lateral root development. We show that VLCFA-Cers, which are synthesized predominantly in the outermost cells, bind to the lipid-binding domain of ATML1. Importantly, this cell type-specific protein-lipid association alters the activity of ATML1 protein and consequently restricts its expression to the protoderm/epidermis through a transcriptional feedback loop. Furthermore, establishment of a compartment, enriched with VLCFA-containing sphingolipids, at the outer lateral membrane facing the external environment may function as a determinant of protodermal cell fate. Taken together, our results indicate that VLCFA-Cers play a pivotal role in directing protoderm/epidermis differentiation by mediating positional signals to ATML1.
  
  This article has an associated ‘The people behind the papers’ interview.
  The Company of Biologists, Scientific journal
  DOI：https://doi.org/10.1242/dev.194969
  DOI ID：10.1242/dev.194969, ISSN：0950-1991, eISSN：1477-9129
• Altered metabolism of chloroplastic NAD kinase-overexpressing Arabidopsis in response to magnesium sulfate supplementation.　　　　　　　　　　　　　　　
  Maki Kawai-Yamada; Atsuko Miyagi; Yuki Sato; Yuki Hosoi; Shin-Nosuke Hashida; Toshiki Ishikawa; Masatoshi Yamaguchi
  Plant signaling & behavior, Volume：16, Number：1, First page：1844509, Last page：1844509, Nov. 2020, ［International magazine］
  Nicotinamide adenine dinucleotide (NAD)/NAD phosphate (NADPH) is essential for numerous redox reactions and serve as co-factors in multiple metabolic processes in all organisms. NAD kinase (NADK) is an enzyme involved in the synthesis of NADP+ from NAD+ and ATP. Arabidopsis NADK2 (AtNADK2) is a chloroplast-localizing enzyme that provides recipients of reducing power in photosynthetic electron transfer. When Arabidopsis plants were grown on MS medium supplemented with 5 mM MgSO4, an AtNADK2-overexpressing line exhibited higher glutathione and total sulfur accumulation than control plants. Metabolomic analysis of major amino acids and organic acids using capillary electrophoresis-mass spectrometry demonstrated that overexpression of AtNADK2 affected a range of metabolic processes in response to MgSO4 supplementation.
  English, Scientific journal
  DOI：https://doi.org/10.1080/15592324.2020.1844509
  DOI ID：10.1080/15592324.2020.1844509, PubMed ID：33210985, PubMed Central ID：PMC7781788
• An Arabidopsis NAC domain transcription factor, ATAF2, promotes age-dependent and dark-induced leaf senescence.　　　　　　　　　　　　　　　
  Isura Sumeda Priyadarshana Nagahage; Shingo Sakamoto; Minoru Nagano; Toshiki Ishikawa; Nobutaka Mitsuda; Maki Kawai-Yamada; Masatoshi Yamaguchi
  Physiologia plantarum, Volume：170, Number：2, First page：299, Last page：308, Oct. 2020, ［International magazine］
  Leaf senescence is controlled developmentally and environmentally and is affected by numerous genes, including transcription factors. An Arabidopsis NAC domain transcription factor, ATAF2, is known to regulate biotic stress responses. Recently, we have demonstrated that ATAF2 upregulates ORE1, a key regulator of leaf senescence. Here, to investigate the function of ATAF2 in leaf senescence further, we generated and analyzed overexpressing transgenic and T-DNA inserted mutant lines. Transient expression analysis indicated that ATAF2 upregulates several NAC domain transcription factors that regulate senescence. Indeed, ATAF2 overexpression induced the expression of senescence-related genes, thereby accelerating leaf senescence, whereas the expression of such genes in ataf2 mutants was lower than that of wild-type plants. Furthermore, the ataf2 mutants exhibited significant delays in dark-induced leaf senescence. It was also found that ATAF2 induces the expression of transcription factors, which both promotes and represses leaf senescence. The present study demonstrates that ATAF2 promotes leaf senescence in response to developmental and environmental signals.
  English, Scientific journal
  DOI：https://doi.org/10.1111/ppl.13156
  DOI ID：10.1111/ppl.13156, PubMed ID：32579231
• Metabolome analysis of rice leaves to obtain low-oxalate strain from ion beam-mutagenised population.　　　　　　　　　　　　　　　
  Atsuko Miyagi; Takuya Saimaru; Nozomi Harigai; Yutaka Oono; Yoshihiro Hase; Maki Kawai-Yamada
  Metabolomics : Official journal of the Metabolomic Society, Volume：16, Number：9, First page：94, Last page：94, Sep. 2020, ［International magazine］
  INTRODUCTION: Rice leaves and stems, which can be used as rice straw for livestock feed, accumulate soluble oxalate. The oxalate content often reaches 5% of the dry weight leaves. Excess uptake of oxalate-rich plants causes mineral deficiencies in vertebrates, so it is important to reduce the oxalate content in rice leaves to produce high-quality rice straw. However, the mechanism of oxalate accumulation in rice has remained unknown. OBJECTIVES: To understand metabolic networks relating oxalate accumulation in rice. METHODS: In this study, we performed metabolome analysis of rice M2 population generated by ion-beam irradiation using CE-MS. RESULTS: The result showed wide variation of oxalate contents in M2 plants compared with those of control plants. Multivariate analyses of metabolome dataset revealed that oxalate accumulation was strongly related with anionic compounds such as 2OG and succinate. For low-oxalate plants, four patterns of metabolic alterations affected oxalate contents in the M2 leaves were observed. In M3 plants, we found putative low-oxalate line obtained from low-oxalate M2 mutant. CONCLUSIONS: These findings would lead to produce the low-oxalate rice and to understand the oxalate synthesis in plants.These findings would lead to produce the low-oxalate rice and to understand the oxalate synthesis in plants.
  English, Scientific journal
  DOI：https://doi.org/10.1007/s11306-020-01713-y
  DOI ID：10.1007/s11306-020-01713-y, PubMed ID：32894362
• Quantitative and Qualitative Analyses of Triacylglycerol Production in the Wild-Type Cyanobacterium Synechocystis sp. PCC 6803 and the Strain Expressing AtfA from Acinetobacter baylyi ADP1.　　　　　　　　　　　　　　　
  Motoki Tanaka; Toshiki Ishikawa; So Tamura; Yujiro Saito; Maki Kawai-Yamada; Yukako Hihara
  Plant & cell physiology, Volume：61, Number：9, First page：1537, Last page：1547, Sep. 2020, ［Domestic magazine］
  Although cyanobacteria do not possess wax ester synthase/acyl-CoA:diacylglycerol acyltransferase (WS/DGAT), the bacterial enzyme for triacylglycerol (TAG) production, there have been several studies reporting the accumulation of TAG-like compounds in cyanobacteria. In this study, we aimed to evaluate TAG productivity of the ΔrecJ::atfA strain of Synechocystis sp. PCC 6803 generated by inserting atfA encoding WS/DGAT from Acinetobacter baylyi ADP1 into recJ (sll1354), together with the wild type (WT) and the gene-disrupted strain of slr2103 having homology with eukaryotic DGAT2 gene family (Δ2103). Thin-layer chromatography (TLC) of neutral lipids or isolation of the neutral lipid-enriched fraction followed by gas chromatography or liquid chromatography-tandem mass spectrometry was employed for analyses. The ΔrecJ::atfA strain accumulated 0.508 nmol ml-1OD730-1 of TAG after a week of incubation at 100 μmol photons m-2 s-1. The saturated fatty acids C16:0 and C18:0 accounted for about 50% and 20% of the TAG fatty acids, respectively, suggesting that de novo-synthesized fatty acids were preferentially incorporated into TAG molecules. When the neutral lipid profile of the lipid extracts was examined by TLC, a spot located in a slightly lower position compared with the TAG standard was detected in WT but not in the Δ2103 strain. TAG accumulation levels of both strains was only 0.01-0.03 nmol ml-1OD730-1, but the fatty acid composition was substantially different from that of the background. These results suggest that trace amounts of TAG can be produced in Synechocystis cells by enzymes other than Slr2103, and major constituents of the TAG-like spot are unknown lipid species produced by Slr2103.
  English, Scientific journal
  DOI：https://doi.org/10.1093/pcp/pcaa069
  DOI ID：10.1093/pcp/pcaa069, PubMed ID：32433767
• Generation of Arabidopsis lines with a red fluorescent marker for endoplasmic reticulum using a tail-anchored protein cytochrome b5 -B.　　　　　　　　　　　　　　　
  Minoru Nagano; Haruko Ueda; Yoichiro Fukao; Maki Kawai-Yamada; Ikuko Hara-Nishimura
  Plant signaling & behavior, Volume：15, Number：9, First page：1790196, Last page：1790196, Sep. 2020, ［International magazine］
  The endoplasmic reticulum (ER) is a multifunctional organelle that performs multiple cellular activities in eukaryotes. Visualizing ER using fluorescent proteins is a powerful method of analyzing its dynamics and to understand its functions. However, red fluorescent proteins with both an N-terminal signal peptide (SP) and a C-terminal ER retention tetrapeptide (HDEL) often cause mislocalization to vacuoles or extracellular spaces when they are constitutively expressed in Arabidopsis. To obtain a red fluorescent ER marker, we selected Arabidopsis cytochrome b5 -B (Cb5-B), a tail-anchored (TA) protein on the ER membrane. Its localization is determined by the transmembrane domain (TMD) and tail domain at the C-terminus. We fused the TMD and the tail domain of Cb5-B to the C-terminus of a red fluorescent protein, tdTomato (tdTomato-CTT). When tdTomato-CTT was constitutively expressed under the ubiquitin10 promoter in Arabidopsis, the fluorescent signal was exclusively detected at the ER by means of the reliable ER marker SP-GFP-HDEL. Therefore, tdTomato-CTT can accurately visualize the ER in stable Arabidopsis lines. Additionally, transient assays showed that tdTomato-CTT can also be used as an ER marker in onion, rice, and Nicotiana benthamiana. We believe that TA proteins could be used to generate various organellar membrane markers in plants.
  English, Scientific journal
  DOI：https://doi.org/10.1080/15592324.2020.1790196
  DOI ID：10.1080/15592324.2020.1790196, PubMed ID：32633191
• Phosphorus toxicity disrupts Rubisco activation and reactive oxygen species defence systems by phytic acid accumulation in leaves.　　　　　　　　　　　　　　　
  Daisuke Takagi; Atsuko Miyagi; Youshi Tazoe; Mao Suganami; Maki Kawai-Yamada; Akihiro Ueda; Yuji Suzuki; Ko Noguchi; Naoki Hirotsu; Amane Makino
  Plant, cell & environment, Volume：43, Number：9, First page：2033, Last page：2053, Sep. 2020, [Reviewed], ［International magazine］
  Phosphorus (P) is an essential mineral nutrient for plants. Nevertheless, excessive P accumulation in leaf mesophyll cells causes necrotic symptoms in land plants; this phenomenon is termed P toxicity. However, the detailed mechanisms underlying P toxicity in plants have not yet been elucidated. This study aimed to investigate the molecular mechanism of P toxicity in rice. We found that under excessive inorganic P (Pi) application, Rubisco activation decreased and photosynthesis was inhibited, leading to lipid peroxidation. Although the defence systems against reactive oxygen species accumulation were activated under excessive Pi application conditions, the Cu/Zn-type superoxide dismutase activities were inhibited. A metabolic analysis revealed that excessive Pi application led to an increase in the cytosolic sugar phosphate concentration and the activation of phytic acid synthesis. These conditions induced mRNA expression of genes that are activated under metal-deficient conditions, although metals did accumulate. These results suggest that P toxicity is triggered by the attenuation of both photosynthesis and metal availability within cells mediated by phytic acid accumulation. Here, we discuss the whole phenomenon of P toxicity, beginning from the accumulation of Pi within cells to death in land plants.
  English, Scientific journal
  DOI：https://doi.org/10.1111/pce.13772
  DOI ID：10.1111/pce.13772, ORCID：71982429, PubMed ID：32281116
• Dehydroascorbate Reductases and Glutathione Set a Threshold for High-Light-Induced Ascorbate Accumulation.　　　　　　　　　　　　　　　
  Yusuke Terai; Hiromi Ueno; Takahisa Ogawa; Yoshihiro Sawa; Atsuko Miyagi; Maki Kawai-Yamada; Takahiro Ishikawa; Takanori Maruta
  Plant physiology, Volume：183, Number：1, First page：112, Last page：122, May 2020, [Reviewed], ［International magazine］
  Plants require a high concentration of ascorbate as a redox buffer for survival under stress conditions, such as high light. Dehydroascorbate reductases (DHARs) are enzymes that catalyze the reduction of DHA to ascorbate using reduced glutathione (GSH) as an electron donor, allowing rapid ascorbate recycling. However, a recent study using an Arabidopsis (Arabidopsis thaliana) triple mutant lacking all three DHAR genes (herein called ∆dhar) did not find evidence for their role in ascorbate recycling under oxidative stress. To further study the function of DHARs, we generated ∆dhar Arabidopsis plants as well as a quadruple mutant line combining ∆dhar with an additional vtc2 mutation that causes ascorbate deficiency. Measurements of ascorbate in these mutants under low- or high-light conditions indicated that DHARs have a nonnegligible impact on full ascorbate accumulation under high light, but that they are dispensable when ascorbate concentrations are low to moderate. Because GSH itself can reduce DHA nonenzymatically, we used the pad2 mutant that contains ∼30% of the wild-type GSH level. The pad2 mutant accumulated ascorbate at a wild-type level under high light; however, when the pad2 mutation was combined with ∆dhar, there was near-complete inhibition of high-light-dependent ascorbate accumulation. The lack of ascorbate accumulation was consistent with a marked increase in the ascorbate degradation product threonate. These findings indicate that ascorbate recycling capacity is limited in ∆dhar pad2 plants, and that both DHAR activity and GSH content set a threshold for high-light-induced ascorbate accumulation.
  English, Scientific journal
  DOI：https://doi.org/10.1104/pp.19.01556
  DOI ID：10.1104/pp.19.01556, PubMed ID：32205453, PubMed Central ID：PMC7210653
• Measurement of Chloroplastic NAD Kinase Activity and Whole Tissue NAD Kinase Assay　　　　　　　　　　　　　　　
  Yuma Ishikawa; Maki Kawai-Yamada; Shin-nosuke Hashida
  BIO-PROTOCOL, Volume：10, Number：1, 2020
  Bio-Protocol, {LLC}, English, Scientific journal
  DOI：https://doi.org/10.21769/bioprotoc.3480
  DOI ID：10.21769/bioprotoc.3480, ISSN：2331-8325, ORCID：83058164
• Plant-Unique cis/trans Isomerism of Long-Chain Base Unsaturation is Selectively Required for Aluminum Tolerance Resulting from Glucosylceramide-Dependent Plasma Membrane Fluidity.　　　　　　　　　　　　　　　
  Masaya Sato; Minoru Nagano; Song Jin; Atsuko Miyagi; Masatoshi Yamaguchi; Maki Kawai-Yamada; Toshiki Ishikawa
  Plants (Basel, Switzerland), Volume：9, Number：1, First page：19, Dec. 2019, [Reviewed], ［International magazine］
  Cis/trans isomerism of the Δ8 unsaturation of long-chain base (LCB) is found only in plant sphingolipids. This unique geometry is generated by sphingolipid LCB Δ8 desaturase SLD which produces both isomers at various ratios, resulting in diverse cis/trans ratios in plants. However, the biological significance of this isomeric diversity remains controversial. Here, we show that the plant-specific cis unsaturation of LCB selectively contributes to glucosylceramide (GlcCer)-dependent tolerance to aluminum toxicity. We established three transgenic rice lines with altered LCB unsaturation profiles. Overexpression of SLD from rice (OsSLD-OX), which preferentially exhibits cis-activity, or Arabidopsis (AtSLD-OX), showing preference for trans-activity, facilitated Δ8 unsaturation in different manners: a slight increase of cis-unsaturated glycosylinositolphosphoceramide (GIPC) in OsSLD-OX, and a drastic increase of trans-unsaturated GlcCer and GIPC in AtSLD-OX. Disruption of LCB Δ4 desaturase (des) significantly decreased the content of GlcCer. Fluorescence imaging analysis revealed that OsSLD-OX and AtSLD-OX showed increased plasma membrane fluidity, whereas des had less fluidity, demonstrating that the isomers universally contributed to increasing membrane fluidity. However, the results of a hydroponic assay showed decreased aluminum tolerance in AtSLD-OX and des compared to OsSLD-OX and the control plants, which did not correlate with membrane fluidity. These results suggest that cis-unsaturated GlcCer, not GIPC, selectively serves to maintain the membrane fluidity specifically associated with aluminum tolerance.
  English, Scientific journal
  DOI：https://doi.org/10.3390/plants9010019
  DOI ID：10.3390/plants9010019, PubMed ID：31877922, PubMed Central ID：PMC7020186
• Glycosylinositol phosphoceramide-specific phospholipase D activity catalyzes transphosphatidylation.　　　　　　　　　　　　　　　
  Rumana Yesmin Hasi; Makoto Miyagi; Katsuya Morito; Toshiki Ishikawa; Maki Kawai-Yamada; Hiroyuki Imai; Tatsuya Fukuta; Kentaro Kogure; Kaori Kanemaru; Junji Hayashi; Ryushi Kawakami; Tamotsu Tanaka
  Journal of biochemistry, Volume：166, Number：5, First page：441, Last page：448, Nov. 2019, [Reviewed], ［International magazine］
  Glycosylinositol phosphoceramide (GIPC) is the most abundant sphingolipid in plants and fungi. Recently, we detected GIPC-specific phospholipase D (GIPC-PLD) activity in plants. Here, we found that GIPC-PLD activity in young cabbage leaves catalyzes transphosphatidylation. The available alcohol for this reaction is a primary alcohol with a chain length below C4. Neither secondary alcohol, tertiary alcohol, choline, serine nor glycerol serves as an acceptor for transphosphatidylation of GIPC-PLD. We also found that cabbage GIPC-PLD prefers GIPC containing two sugars. Neither inositol phosphoceramide, mannosylinositol phosphoceramide nor GIPC with three sugar chains served as substrate. GIPC-PLD will become a useful catalyst for modification of polar head group of sphingophospholipid.
  English, Scientific journal
  DOI：https://doi.org/10.1093/jb/mvz056
  DOI ID：10.1093/jb/mvz056, ISSN：0021-924X, PubMed ID：31504617
• High-yielding rice Takanari has superior photosynthetic response to a commercial rice Koshihikari under fluctuating light.　　　　　　　　　　　　　　　
  Shunsuke Adachi; Yu Tanaka; Atsuko Miyagi; Makoto Kashima; Ayumi Tezuka; Yoshihiro Toya; Shunzo Kobayashi; Satoshi Ohkubo; Hiroshi Shimizu; Maki Kawai-Yamada; Rowan F Sage; Atsushi J Nagano; Wataru Yamori
  Journal of experimental botany, Volume：70, Number：19, First page：5287, Last page：5297, Oct. 2019, [Reviewed], ［International magazine］
  Leaves within crop canopies experience variable light over the course of a day, which greatly affects photosynthesis and crop productivity. Little is known about the mechanisms of the photosynthetic response to fluctuating light and their genetic control. Here, we examined gas exchange, metabolite levels, and chlorophyll fluorescence during the photosynthetic induction response in an Oryza sativa indica cultivar with high yield (Takanari) and a japonica cultivar with lower yield (Koshihikari). Takanari had a faster induction response to sudden increases in light intensity than Koshihikari, as demonstrated by faster increases in net CO2 assimilation rate, stomatal conductance, and electron transport rate. In a simulated light regime that mimicked a typical summer day, the faster induction response in Takanari increased daily CO2 assimilation by 10%. The faster response of Takanari was explained in part by its maintenance of a larger pool of Calvin-Benson cycle metabolites. Together, the rapid responses of electron transport rate, metabolic flux, and stomatal conductance in Takanari contributed to the greater daily carbon gain under fluctuating light typical of natural environments.
  English, Scientific journal
  DOI：https://doi.org/10.1093/jxb/erz304
  DOI ID：10.1093/jxb/erz304, ISSN：0022-0957, PubMed ID：31257443, PubMed Central ID：PMC6793460
• Excessive assimilation of ammonium by plastidic glutamine synthetase is a major cause of ammonium toxicity in Arabidopsis thaliana　　　　　　　　　　　　　　　
  Hachiya T; Inaba J; Wakazaki M; Sato M; Toyooka K; Miyagi A; Kawai-Yamada M; Kiba T; Gojon A; Sakakibara H
  bioRxiv, Volume：https://doi.org/10.1101/764324, Sep. 2019
  English, Scientific journal
• Oxalate contents in leaves of two rice cultivars grown at a free-air CO₂ enrichment (FACE) site　　　　　　　　　　　　　　　
  Atsuko Miyagi; Ko Noguchi; Takeshi Tokida; Yasuhiro Usui; Hirofumi Nakamura; Hidemitsu Sakai; Toshihiro Hasegawa; Maki Kawai-Yamada
  Plant Production Science, Volume：22, Number：3, First page：407, Last page：411, Jul. 2019, [Reviewed]
  English, Scientific journal
  DOI：https://doi.org/10.1080/1343943X.2019.1598272
  DOI ID：10.1080/1343943X.2019.1598272
• Mitochondrial AOX Supports Redox Balance of Photosynthetic Electron Transport, Primary Metabolite Balance, and Growth in Arabidopsis thaliana under High Light.　　　　　　　　　　　　　　　
  Jiang Z; Watanabe CKA; Miyagi A; Kawai-Yamada M; Terashima I; Noguchi K
  International journal of molecular sciences, Volume：20, Number：12, Jun. 2019, [Reviewed]
  DOI：https://doi.org/10.3390/ijms20123067
  DOI ID：10.3390/ijms20123067, PubMed ID：31234590
• One of the NAD kinases, sll1415, is required for the glucose metabolism of Synechocystis sp. PCC 6803.　　　　　　　　　　　　　　　
  Ishikawa Y; Miyagi A; Ishikawa T; Nagano M; Yamaguchi M; Hihara Y; Kaneko Y; Kawai-Yamada M
  The Plant journal : for cell and molecular biology, Volume：98, Number：4, First page：654, Last page：666, May 2019, [Reviewed], ［International magazine］
  Pyridine nucleotides (NAD(P)(H)) are electron carriers that are the driving forces in various metabolic pathways. Phosphorylation of NAD(H) to NADP(H) is performed by the enzyme NAD kinase (NADK). Synechocystis sp. PCC 6803 harbors two genes (sll1415 and slr0400) that encode proteins with NADK homology. When genetic mutants for sll1415 and slr0400 (Δ1415 and Δ0400, respectively) were cultured under photoheterotrophic growth conditions only the Δ1415 cells showed a growth defect. In wild-type cells, the sll1415 transcript accumulated after the cells were transferred to photoheterotrophic conditions. Furthermore, NAD(P)(H) measurements demonstrated that a dynamic metabolic conversion was implemented during the adaptation from photoautotrophic to photoheterotrophic conditions. Electron microscopy observation and biochemistry quantification demonstrated the accumulation of glycogen in the Δ1415 cells under photoheterotrophic conditions at 96 h. Quantitative real-time reverse transcription PCR (qRT-PCR) demonstrated the accumulation of mRNAs that encoded glycogen biosynthesis-related enzymes in photoheterotrophic Δ1415 cells. At 96 h, enzyme activity measurement in the photoheterotrophic Δ1415 cells demonstrated that the activities of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase were decreased, but the activities of glucose dehydrogenase were increased. Furthermore, metabolomics analysis demonstrated that the Δ1415 cells showed increased glucose-6-phosphate and 6-phosphogluconate content at 96 h. Therefore, sll1415 has a significant function in the oxidative pentose phosphate (OPP) pathway for catabolism of glucose under photoheterotrophic conditions. Additionally, it is presumed that the slr0400 had a different role in glucose catabolism during growth. These results suggest that the two Synechocystis sp. PCC 6803 NADKs (Sll1415 and Slr0400) have distinct functions in photoheterotrophic cyanobacterial metabolism.
  English, Scientific journal
  DOI：https://doi.org/10.1111/tpj.14262
  DOI ID：10.1111/tpj.14262, ISSN：0960-7412, PubMed ID：30693583
• Detection of Disulfides in Protein Extracts of Arabidopsis thaliana Using Monobromobimane (mBB)　　　　　　　　　　　　　　　
  Shin-nosuke Hashida; Maki Kawai-Yamada
  BIO-PROTOCOL, Volume：9, Number：5, 2019
  Bio-Protocol, {LLC}, English, Scientific journal
  DOI：https://doi.org/10.21769/bioprotoc.3183
  DOI ID：10.21769/bioprotoc.3183, ISSN：2331-8325, ORCID：83058156
• Metabolic and biochemical responses of Potamogeton anguillanus Koidz. (Potamogetonaceae) to low oxygen conditions.　　　　　　　　　　　　　　　
  Parveen M; Miyagi A; Kawai-Yamada M; Rashid MH; Asaeda T
  Journal of plant physiology, Volume：232, First page：171, Last page：179, Jan. 2019, [Reviewed]
  DOI：https://doi.org/10.1016/j.jplph.2018.11.023
  DOI ID：10.1016/j.jplph.2018.11.023, ISSN：0176-1617, PubMed ID：30537604
• Arabidopsis Bax inhibitor-1 interacts with enzymes related to very-long-chain fatty acid synthesis.　　　　　　　　　　　　　　　
  Nagano M; Kakuta C; Fukao Y; Fujiwara M; Uchimiya H; Kawai-Yamada M
  Journal of plant research, Volume：132, Number：1, First page：131, Last page：143, Jan. 2019, [Reviewed]
  Springer Science and Business Media LLC, Scientific journal
  DOI：https://doi.org/10.1007/s10265-018-01081-8
  DOI ID：10.1007/s10265-018-01081-8, ISSN：0918-9440, eISSN：1618-0860, PubMed ID：30604175
• Physiological Significance of NAD Kinases in Cyanobacteria.　　　　　　　　　　　　　　　
  Ishikawa Y; Kawai-Yamada M
  Frontiers in plant science, Volume：10, First page：847, 2019, [Reviewed]
  DOI：https://doi.org/10.3389/fpls.2019.00847
  DOI ID：10.3389/fpls.2019.00847, PubMed ID：31316540
• Inter-Organelle NAD Metabolism Underpinning Light Responsive NADP Dynamics in Plants.　　　　　　　　　　　　　　　
  Hashida SN; Kawai-Yamada M
  Frontiers in plant science, Volume：10, First page：960, 2019, [Reviewed]
  DOI：https://doi.org/10.3389/fpls.2019.00960
  DOI ID：10.3389/fpls.2019.00960, PubMed ID：31404160
• Effects of inactivation of the cyAbrB2 transcription factor together with glycogen synthesis on cellular metabolism and free fatty acid production in the cyanobacterium Synechocystis sp. PCC 6803.　　　　　　　　　　　　　　　
  Yuta Kodama; Akihito Kawahara; Atsuko Miyagi; Toshiki Ishikawa; Maki Kawai-Yamada; Yasuko Kaneko; Yasushi Takimura; Yukako Hihara
  Biotechnology and Bioengineering, Volume：115, Number：12, First page：2974, Last page：2985, Dec. 2018, [Reviewed]
  English, Scientific journal
  DOI：https://doi.org/10.1002/bit.26842
  DOI ID：10.1002/bit.26842, ISSN：1097-0290
• A homologue of dihydrosphingosine C4 hydroxylase gene family member, DSH5, that shows spatial expression in rice; its ectopic expression leads to a lethal phenotype.　　　　　　　　　　　　　　　
  Tomohiro Imamura; Chihiro Obata; Kazuyoshi Yoneyama; Masatoshi Ichikawa; Akane Ikura; Hiromi Mutsuro-Aoki; Toshiki Ishikawa; Maki Kawai-Yamada; Tadamasa Sasaki; Hiroaki Kusano; Hiroaki Shimada
  GENES & GENETIC SYSTEMS, Volume：93, First page：135, Last page：142, Oct. 2018, [Reviewed]
  English
  DOI：https://doi.org/10.1266/ggs/17-00054
  DOI ID：10.1266/ggs/17-00054
• An NAC domain transcription factor ATAF2 acts as transcriptional activator or repressor dependent on promoter context　　　　　　　　　　　　　　　
  Isura Sumeda Priyadarshana Nagahage; Shingo Sakamoto; Minoru Nagano; Toshiki Ishikawa; Maki Kawai-Yamada; Nobutaka Mitsuda; Masatoshi Yamaguchi
  Plant Biotechnology, Volume：35, Number：3, First page：285, Last page：289, Sep. 2018, [Reviewed]
  English, Scientific journal
  DOI：https://doi.org/10.5511/plantbiotechnology.18.0507a
  DOI ID：10.5511/plantbiotechnology.18.0507a
• Ferredoxin/thioredoxin system plays an important role in the chloroplastic NADP status of Arabidopsis.　　　　　　　　　　　　　　　
  Hashida SN; Miyagi A; Nishiyama M; Yoshida K; Hisabori T; Kawai-Yamada M
  The Plant journal : for cell and molecular biology, Volume：95, Number：6, First page：947, Last page：960, Sep. 2018, [Reviewed]
  DOI：https://doi.org/10.1111/tpj.14000
  DOI ID：10.1111/tpj.14000, ISSN：0960-7412, PubMed ID：29920827
• DSH5, a dihydrosphingosine C4 hydroxylase gene family member, shows spatially restricted expression in rice and is lethal when expressed ectopically.　　　　　　　　　　　　　　　
  Imamura T; Obata C; Yoneyama K; Ichikawa M; Ikura A; Mutsuro-Aoki H; Ishikawa T; Kawai-Yamada M; Sasaki T; Kusano H; Shimada H
  Genes & genetic systems, Volume：93, Number：4, First page：135, Last page：142, Sep. 2018, [Reviewed], ［Domestic magazine］
  Dihydrosphingosine C4 hydroxylase (DSH), a diiron-binding membrane enzyme, catalyzes the hydration of dihydrosphingosine and acyl-sphinganine to produce phytosphingosine and phytoceramide, respectively. Rice has two types of DSH homologs: general DSHs, namely DSH1, DSH2 and DSH4, and others that show spatial expression profiles, namely DSH3 and DSH5. The general DSHs exist in many plant species. These DSHs showed similarity in their functions and complemented the yeast sur2D mutation. In contrast, homologs of DSH3 and DSH5 were found only in monocot plants. Phylogenetic analysis placed these DSHs in different clades that are evolutionarily divergent from those of the general DSHs. DSH3 and DSH5 showed low-level expression. DSH5 expression was specifically in vascular bundle tissues. Ectopic expression of DSH5 induced a dwarf phenotype characterized by severe growth inhibition and an increase in the thickness of the leaf body caused by enlargement of bulliform cells in the leaves. However, no significant difference was observed in the amount of sphingolipid species. DSH5 did not complement the yeast sur2D mutation, implying that DSH5 has little effect on sphingolipid metabolism. These findings suggested that DSH3 and DSH5 originated and diverged in monocot plants.
  English, Scientific journal
  DOI：https://doi.org/10.1266/ggs.17-00054
  DOI ID：10.1266/ggs.17-00054, ISSN：1341-7568, PubMed ID：30185720
• Suppression of Arabidopsis GGLT1 affects growth by reducing the L-galactose content and borate cross-linking of rhamnogalacturonan-II.　　　　　　　　　　　　　　　
  Sechet J; Htwe S; Urbanowicz B; Agyeman A; Feng W; Ishikawa T; Colomes M; Kumar KS; Kawai-Yamada M; Dinneny JR; O'Neill MA; Mortimer JC
  The Plant journal : for cell and molecular biology, Sep. 2018, [Reviewed]
  DOI：https://doi.org/10.1111/tpj.14088
  DOI ID：10.1111/tpj.14088, ISSN：0960-7412, PubMed ID：30203879
• Effects of inactivation of the cyAbrB2 transcription factor together with glycogen synthesis on cellular metabolism and free fatty acid production in the cyanobacterium Synechocystis sp. PCC 6803.　　　　　　　　　　　　　　　
  Kodama Y; Kawahara A; Miyagi A; Ishikawa T; Kawai-Yamada M; Kaneko Y; Takimura Y; Hihara Y
  Biotechnology and bioengineering, Sep. 2018, [Reviewed]
  DOI：https://doi.org/10.1002/bit.26842
  DOI ID：10.1002/bit.26842, ISSN：0006-3592, PubMed ID：30252943
• GLUCOSAMINE INOSITOLPHOSPHORYLCERAMIDE TRANSFERASE1 (GINT1) Is a GlcNAc-Containing Glycosylinositol Phosphorylceramide Glycosyltransferase.　　　　　　　　　　　　　　　
  Ishikawa T; Fang L; Rennie EA; Sechet J; Yan J; Jing B; Moore W; Cahoon EB; Scheller HV; Kawai-Yamada M; Mortimer JC
  Plant physiology, Volume：177, Number：3, First page：938, Last page：952, Jul. 2018, [Reviewed]
  DOI：https://doi.org/10.1104/pp.18.00396
  DOI ID：10.1104/pp.18.00396, ISSN：0032-0889, PubMed ID：29760197
• Effects of Elevated Atmospheric CO 2 on Respiratory Rates in Mature Leaves of Two Rice Cultivars Grown at a Free-Air CO 2 Enrichment Site and Analyses of the Underlying Mechanisms　　　　　　　　　　　　　　　
  Ko Noguchi; Tomonori Tsunoda; Atsuko Miyagi; Maki Kawai-Yamada; Daisuke Sugiura; Shin-Ichi Miyazawa; Takeshi Tokida; Yasuhiro Usui; Hirofumi Nakamura; Hidemitsu Sakai; Toshihiro Hasegawa
  Plant and Cell Physiology, Volume：59, Number：3, First page：637, Last page：649, Mar. 2018, [Reviewed]
  Respiratory CO 2 efflux and O 2 uptake rates in leaves change in response to the growth CO 2 concentration ([CO 2 ]). The degrees of change vary depending on the responses of cellular processes such as nitrogen (N) assimilation and accumulation of organic acids to growth [CO 2 ]. However, the underlying mechanisms remain unclear. Here, we examined the respiratory characteristics of mature leaves of two rice varieties with different yield capacities at different growth stages under ambient and elevated [CO 2 ] conditions at a free-air CO 2 enrichment site. We also examined the effect of increased water temperature on leaf respiration. We measured the rates of CO 2 efflux and O 2 uptake, and determined N contents, primary metabolite contents and maximal activities of respiratory enzymes. The leaf CO 2 efflux rates decreased in plants grown at elevated [CO 2 ] in both varieties, and were higher in high-yielding Takanari than in Koshihikari. The leaf O 2 uptake rates showed little change with respect to growth [CO 2 ] and variety. The increased water temperature did not significantly affect the CO 2 efflux and O 2 uptake rates. The N and amino acid contents were significantly higher in Takanari than in Koshihikari. The enhanced N assimilation in Takanari may have consumed more respiratory NADH, leading to higher CO 2 efflux rates. In Koshihikari, the ratio of tricarboxylic acid (TCA) cycle intermediates changed and maximal activities of enzymes in the TCA cycle decreased at elevated [CO 2 ]. Therefore, the decreased rates of CO 2 efflux in Koshihikari may be due to the decreased activities of TCA cycle enzymes at elevated [CO 2 ].
  Oxford University Press, English, Scientific journal
  DOI：https://doi.org/10.1093/pcp/pcy017
  DOI ID：10.1093/pcp/pcy017, ISSN：1471-9053, PubMed ID：29401364, SCOPUS ID：85043253711
• Evaluation of metabolic changes in oxalate-rich plant Rumex obtusifolius L. caused by ion beam irradiation.　　　　　　　　　　　　　　　
  Atsuko Miyagi; Sayaka Kitano; Yutaka Oono; Yoshihiro Hase; Issay Narumi; Masatoshi Yamaguchi; Hirofumi Uchimiya; Maki Kawai-Yamada
  Plant physiology and biochemistry : PPB, Volume：122, First page：40, Last page：45, Jan. 2018, [Reviewed], ［International magazine］
  Some Rumex species such as sorrel are edible as baby leaf salad greens. On the other hand, Rumex plants accumulate soluble oxalate, a toxic metabolite which causes serious diseases such as renal syndrome. We attempted to produce low-oxalate plants of R. obtusifolius, a perennial weed which has higher vitamin C and amino acid content and higher tolerance to stress than many other Rumex species. Ion beams are ionising radiation with high linear energy transfer that causes a wide spectrum of mutations. Thus, in the present study we evaluated the effects of ion beams on oxalate and other primary metabolites in leaves of R. obtusifolius using CE-MS. The results showed that oxalate content was increased by irradiation with carbon ion beams. Metabolome analysis revealed that ion beams affected carbon flow to the isocitrate pathway, which is involved in oxalate synthesis. These observations suggested that modulation of carbon flow to the isocitrate pathway is important to regulate oxalate levels in plants.
  English, Scientific journal
  DOI：https://doi.org/10.1016/j.plaphy.2017.11.001
  DOI ID：10.1016/j.plaphy.2017.11.001, ISSN：0981-9428, PubMed ID：29172104
• Synergistic effects of light quality, carbon dioxide and nutrients on metabolite compositions of head lettuce under artificial growth conditions mimicking a plant factory　　　　　　　　　　　　　　　
  Atsuko Miyagi; Hirofumi Uchimiya; Maki Kawai-Yamada
  FOOD CHEMISTRY, Volume：218, First page：561, Last page：568, Mar. 2017, [Reviewed]
  Carbon dioxide (CO2), nutrient supply, and light quality are amongst the major controlling factors to improve the biomass production and nutritional outputs in plant factory. The present study employed CE-MS to investigate the effects of high CO2, nutrient formulation, and LED on the accumulation of primary metabolites in head lettuce. Results suggested that high CO2 (1000 ppm) and nutrient supply enhanced both the biomass and some amino acids. Hierarchical clustering analysis was used to evaluate effects of red LED in combination with high CO2 and Hoagland's formulation; distinctive cluster formation contained 14 amino acids (mostly branched-chain and aromatic amino acids, histidine and arginine). Thus, simultaneous treatments of monochromatic LED, high CO2 and nutrient formulation improved the amino acids accumulation, and likely reduced the inorganic nitrogen sources in planta. (C) 2016 Elsevier Ltd. All rights reserved.
  ELSEVIER SCI LTD, English, Scientific journal
  DOI：https://doi.org/10.1016/j.foodchem.2016.09.102
  DOI ID：10.1016/j.foodchem.2016.09.102, ISSN：0308-8146, eISSN：1873-7072, ORCID：45646351, Web of Science ID：WOS:000386409700073
• CE–MS-based metabolomics reveals the metabolic profile of maitake mushroom (Grifola frondosa) strains with different cultivation characteristics　　　　　　　　　　　　　　　
  Mayumi Sato; Atsuko Miyagi; Shozo Yoneyama; Seiki Gisusi; Yoshihiko Tokuji; Maki Kawai-Yamada
  Bioscience, Biotechnology and Biochemistry, Volume：81, Number：12, First page：2314, Last page：2322, 2017, [Reviewed]
  Maitake mushroom (Grifola frondosa [Dicks.] Gray) is generally cultured using the sawdust of broadleaf trees. The maitake strain Gf433 has high production efficiency, with high-quality of fruiting bodies even when 30% of the birch sawdust on the basal substrate is replaced with conifer sawdust. We performed metabolome analysis to investigate the effect of different cultivation components on the metabolism of Gf433 and Mori52 by performing CE–MS on their fruiting bodies in different cultivation conditions to quantify the levels of amino acids, organic acids, and phosphorylated organic acids. We found that amino acid and organic acid content in Gf433 were not affected by the kind of sawdust. However, Gf433 contained more organic acids and less amino acids than Mori52, and Gf433 also contained more chitin compared with Mori52. We believe that these differences in the metabolome contents of the two strains are related to the high production efficiency of Gf433.
  Japan Society for Bioscience Biotechnology and Agrochemistry, English, Scientific journal
  DOI：https://doi.org/10.1080/09168451.2017.1387049
  DOI ID：10.1080/09168451.2017.1387049, ISSN：1347-6947, ORCID：45646350, PubMed ID：29050513, SCOPUS ID：85038389198, Web of Science ID：WOS:000423159400012
• Loss of Inositol Phosphorylceramide Sphingolipid Mannosylation Induces Plant Immune Responses and Reduces Cellulose Content in Arabidopsis　　　　　　　　　　　　　　　
  Lin Fang; Toshiki Ishikawa; Emilie A. Rennie; Gosia M. Murawska; Jeemeng Lao; Jingwei Yan; Alex Yi-Lin Tsai; Edward E. K. Baidoo; Jun Xu; Jay D. Keasling; Taku Demura; Maki Kawai-Yamada; Henrik V. Scheller; Jenny C. Mortimer
  PLANT CELL, Volume：28, Number：12, First page：2991, Last page：3004, Dec. 2016, [Reviewed]
  Glycosylinositol phosphorylceramides (GIPCs) are a class of glycosylated sphingolipids found in plants, fungi, and protozoa. These lipids are abundant in the plant plasma membrane, forming; 25% of total plasma membrane lipids. Little is known about the function of the glycosylated headgroup, but two recent studies have indicated that they play a key role in plant signaling and defense. Here, we show that a member of glycosyltransferase family 64, previously named ECTOPICALLY PARTING CELLS1, is likely a Golgi-localized GIPC-specific mannosyl-transferase, which we renamed GIPC MANNOSYL-TRANSFERASE1 (GMT1). Sphingolipid analysis revealed that the Arabidopsis thaliana gmt1 mutant almost completely lacks mannose-carrying GIPCs. Heterologous expression of GMT1 in Saccharomyces cerevisiae and tobacco (Nicotiana tabacum) cv Bright Yellow 2 resulted in the production of non-native mannosylated GIPCs. gmt1 displays a severe dwarfed phenotype and a constitutive hypersensitive response characterized by elevated salicylic acid and hydrogen peroxide levels, similar to that we previously reported for the Golgi-localized, GIPC-specific, GDP-Man transporter GONST1 (Mortimer et al., 2013). Unexpectedly, we show that gmt1 cell walls have a reduction in cellulose content, although other matrix polysaccharides are unchanged.
  AMER SOC PLANT BIOLOGISTS, English, Scientific journal
  DOI：https://doi.org/10.1105/tpc.16.00186
  DOI ID：10.1105/tpc.16.00186, ISSN：1040-4651, eISSN：1532-298X, ORCID：45646353, PubMed ID：27895225, Web of Science ID：WOS:000393167800009
• Molecular characterization and targeted quantitative profiling of the sphingolipidome in rice　　　　　　　　　　　　　　　
  Toshiki Ishikawa; Yukihiro Ito; Maki Kawai-Yamada
  PLANT JOURNAL, Volume：88, Number：4, First page：681, Last page：693, Nov. 2016, [Reviewed]
  Recent advances in comprehensive metabolite profiling techniques, the foundation of metabolomics, is facilitating our understanding of the functions, regulation and complex networks of various metabolites in organisms. Here, we report a quantitative metabolomics technique for complex plant sphingolipids, composed of various polar head groups as well as structural isomers of hydrophobic ceramide moieties. Rice (Oryza sativa L.) was used as an experimental model of monocotyledonous plants and has been demonstrated to possess a highly complex sphingolipidome including hundreds of molecular species with a wide range of abundance. We established a high-throughput scheme for lipid preparation and mass spectrometry-based characterization of complex sphingolipid structures, which provided basic information to create a comprehensive theoretical library for targeted quantitative profiling of complex sphingolipids in rice. The established sphingolipidomic approach combined with multivariate analyses of the large dataset obtained clearly showed that different classes of rice sphingolipids, particularly including subclasses of glycosylinositol phosphoceramide with various sugar-chain head groups, are distributed with distinct quantitative profiles in various rice tissues, indicating tissue-dependent metabolism and biological functions of the lipid classes and subclasses. The sphingolipidomic analysis also highlighted that disruption of a lipid-associated gene causes a typical sphingolipidomic change in a gene-dependent manner. These results clearly support the utility of the sphingolipidomic approach in application to wide screening of sphingolipid-metabolic phenotypes as well as deeper investigation of metabolism and biological functions of complex sphingolipid species in plants.
  Significance Statement Sphingolipids play vital roles in plants, but the biological implications of their structural diversity remains to be addressed. Here we detail methodological advances for characterizing complex sphingolipid species quantitatively, and demonstrate its utility for profiling tissue-specific sphingolipids and for metabolic fingerprinting of sphingolipid-associated mutants.
  WILEY-BLACKWELL, English, Scientific journal
  DOI：https://doi.org/10.1111/tpj.13281
  DOI ID：10.1111/tpj.13281, ISSN：0960-7412, eISSN：1365-313X, ORCID：45646355, Web of Science ID：WOS:000389928200013
• Increased Rate of NAD Metabolism Shortens Plant Longevity by Accelerating Developmental Senescence in Arabidopsis　　　　　　　　　　　　　　　
  Shin-nosuke Hashida; Taketo Itami; Kentaro Takahara; Takayuki Hirabayashi; Hirofumi Uchimiya; Maki Kawai-Yamada
  PLANT AND CELL PHYSIOLOGY, Volume：57, Number：11, First page：2427, Last page：2439, Nov. 2016, [Reviewed]
  NAD is a well-known co-enzyme that mediates hundreds of redox reactions and is the basis of various processes regulating cell responses to different environmental and developmental cues. The regulatory mechanism that determines the amount of cellular NAD and the rate of NAD metabolism remains unclear. We created Arabidopsis thaliana plants overexpressing the NAD synthase (NADS) gene that participates in the final step of NAD biosynthesis. NADS overexpression enhanced the activity of NAD biosynthesis but not the amounts of NAD(+), NADH, NADP(+) or NADPH. However, the amounts of some intermediates were elevated, suggesting that NAD metabolism increased. The NAD redox state was greatly facilitated by an imbalance between NAD generation and degradation in response to bolting. Metabolite profiling and transcriptional analysis revealed that the drastic modulation of NAD redox homeostasis increased tricarboxylic acid flux, causing the ectopic generation of reactive oxygen species. Vascular bundles suffered from oxidative stress, leading to a malfunction in amino acid and organic acid transportation that caused early wilting of the flower stalk and shortened plant longevity, probably due to malnutrition. We concluded that the mechanism regulating the balance between NAD synthesis and degradation is important in the systemic plant response to developmental cues during the growth-phase transition.
  OXFORD UNIV PRESS, English, Scientific journal
  DOI：https://doi.org/10.1093/pcp/pcw155
  DOI ID：10.1093/pcp/pcw155, ISSN：0032-0781, eISSN：1471-9053, ORCID：45646352, Web of Science ID：WOS:000393158000017
• Metabolomic analysis of NAD kinase-deficient mutants of the cyanobacterium Synechocystis sp PCC 6803　　　　　　　　　　　　　　　
  Yuuma Ishikawa; Atsuko Miyagi; Yuto Haishima; Toshiki Ishikawa; Minoru Nagano; Masatoshi Yamaguchi; Yukako Hihara; Maki Kawai-Yamada
  JOURNAL OF PLANT PHYSIOLOGY, Volume：205, First page：105, Last page：112, Oct. 2016, [Reviewed]
  NAD kinase (NADK) phosphorylates NAD(H) to NADP(H). The enzyme has a crucial role in the regulation of the NADP(H)/NAD(H) ratio in various organisms. The unicellular cyanobacterium Synechocystis sp. PCC 6803 possesses two NADK-encoding genes, sll1415 and slr0400. To elucidate the metabolic change in NADK-deficient mutants growing under photoautotrophic conditions, we conducted metabolomic analysis using capillary electrophoresis mass spectrometry (CE-MS). The growth curves of the wild type parent (WT) and NADK-deficient mutants (Delta 1415 and Delta 0400) did not show any differences under photoautotrophic conditions. The NAD(P)(H) balance showed abnormality in both mutants. However, only the metabolite pattern of Delta 0400 showed differences compared to WT. These results indicated that the two NADK isoforms have distinct functions in cyanobacterial metabolism. (C) 2016 Elsevier GmbH. All rights reserved.
  ELSEVIER GMBH, URBAN & FISCHER VERLAG, English, Scientific journal
  DOI：https://doi.org/10.1016/j.jplph.2016.09.002
  DOI ID：10.1016/j.jplph.2016.09.002, ISSN：0176-1617, eISSN：1618-1328, ORCID：45646354, PubMed ID：27657983, Web of Science ID：WOS:000385858600014
• Plasma Membrane Microdomains Are Essential for Rac1-RbohB/H-Mediated Immunity in Rice　　　　　　　　　　　　　　　
  Minoru Nagano; Toshiki Ishikawa; Masayuki Fujiwara; Yoichiro Fukao; Yoji Kawano; Maki Kawai-Yamada; Ko Shimamoto
  PLANT CELL, Volume：28, Number：8, First page：1966, Last page：1983, Aug. 2016, [Reviewed]
  Numerous plant defense-related proteins are thought to congregate in plasma membrane microdomains, which consist mainly of sphingolipids and sterols. However, the extent to which microdomains contribute to defense responses in plants is unclear. To elucidate the relationship between microdomains and innate immunity in rice (Oryza sativa), we established lines in which the levels of sphingolipids containing 2-hydroxy fatty acids were decreased by knocking down two genes encoding fatty acid 2-hydroxylases (FAH1 and FAH2) and demonstrated that microdomains were less abundant in these lines. By testing these lines in a pathogen infection assay, we revealed that microdomains play an important role in the resistance to rice blast fungus infection. To illuminate the mechanism by which microdomains regulate immunity, we evaluated changes in protein composition, revealing that microdomains are required for the dynamics of the Rac/ROP small GTPase Rac1 and respiratory burst oxidase homologs (Rbohs) in response to chitin elicitor. Furthermore, FAHs are essential for the production of reactive oxygen species (ROS) after chitin treatment. Together with the observation that RbohB, a defense-related NADPH oxidase that interacts with Rac1, is localized in microdomains, our data indicate that microdomains are required for chitin-induced immunity through ROS signaling mediated by the Rac1-RbohB pathway.
  AMER SOC PLANT BIOLOGISTS, English, Scientific journal
  DOI：https://doi.org/10.1105/tpc.16.00201
  DOI ID：10.1105/tpc.16.00201, ISSN：1040-4651, eISSN：1532-298X, ORCID：45646356, Web of Science ID：WOS:000386169200016
• KONJAC1 and 2 Are Key Factors for GDP-Mannose Generation and Affect L-Ascorbic Acid and Glucomannan Biosynthesis in Arabidopsis　　　　　　　　　　　　　　　
  Shota Sawake; Noriaki Tajima; Jenny C. Mortimer; Jeemeng Lao; Toshiki Ishikawa; Xiaolan Yu; Yukiko Yamanashi; Yoshihisa Yoshimi; Maki Kawai-Yamada; Paul Dupree; Yoichi Tsumuraya; Toshihisa Kotake
  PLANT CELL, Volume：27, Number：12, First page：3397, Last page：3409, Dec. 2015, [Reviewed]
  Humans are unable to synthesize L-ascorbic acid (AsA), yet it is required as a cofactor in many critical biochemical reactions. The majority of human dietary AsA is obtained from plants. In Arabidopsis thaliana, a GDP-mannose pyrophosphorylase (GMPP), VITAMIN C DEFECTIVE1 (VTC1), catalyzes a rate-limiting step in AsA synthesis: the formation of GDP-Man. In this study, we identified two nucleotide sugar pyrophosphorylase-like proteins, KONJAC1 (KJC1) and KJC2, which stimulate the activity of VTC1. The kjc1kjc2 double mutant exhibited severe dwarfism, indicating that KJC proteins are important for growth and development. The kjc1 mutation reduced GMPP activity to 10% of wild-type levels, leading to a 60% reduction in AsA levels. On the contrary, overexpression of KJC1 significantly increased GMPP activity. The kjc1 and kjc1kjc2 mutants also exhibited significantly reduced levels of glucomannan, which is also synthesized from GDP-Man. Recombinant KJC1 and KJC2 enhanced the GMPP activity of recombinant VTC1 in vitro, while KJCs did not show GMPP activity. Yeast two-hybrid assays suggested that the stimulation of GMPP activity occurs via interaction of KJCs with VTC1. These results suggest that KJCs are key factors for the generation of GDP-Man and affect AsA level and glucomannan accumulation through the stimulation of VTC1 GMPP activity.
  AMER SOC PLANT BIOLOGISTS, English, Scientific journal
  DOI：https://doi.org/10.1105/tpc.15.00379
  DOI ID：10.1105/tpc.15.00379, ISSN：1040-4651, eISSN：1532-298X, ORCID：45646361, Web of Science ID：WOS:000368297100010
• Glycosylated sphingolipid biosynthesis and function in Arabidopsis
  Jenny C. Mortimer; Toshiki Ishikawa; Lin Fang; Beibei Jing; Emilie Rennie; Noriko Inada; Xiaolan Yu; Jeemeng Lao; Taku Demura; Maki Kawai-Yamada; Henrik Scheller; Paul Dupree
  GLYCOBIOLOGY, Volume：25, Number：11, First page：1266, Last page：1267, Nov. 2015, [Reviewed]
  OXFORD UNIV PRESS INC, English
  ISSN：0959-6658, eISSN：1460-2423, ORCID：45646360, Web of Science ID：WOS:000362991500108
• Overexpression of BAX INHIBITOR-1 Links Plasma Membrane Microdomain Proteins to Stress　　　　　　　　　　　　　　　
  Toshiki Ishikawa; Toshihiko Aki; Shuichi Yanagisawa; Hirofumi Uchimiya; Maki Kawai-Yamada
  PLANT PHYSIOLOGY, Volume：169, Number：2, First page：1333, Last page：1343, Oct. 2015, [Reviewed]
  BAX INHIBITOR-1 (BI-1) is a cell death suppressor widely conserved in plants and animals. Overexpression of BI-1 enhances tolerance to stress-induced cell death in plant cells, although the molecular mechanism behind this enhancement is unclear. We recently found that Arabidopsis (Arabidopsis thaliana) BI-1 is involved in the metabolism of sphingolipids, such as the synthesis of 2-hydroxy fatty acids, suggesting the involvement of sphingolipids in the cell death regulatory mechanism downstream of BI-1. Here, we show that BI-1 affects cell death-associated components localized in sphingolipid-enriched microdomains of the plasma membrane in rice (Oryza sativa) cells. The amount of 2-hydroxy fatty acid-containing glucosylceramide increased in the detergent-resistant membrane (DRM; a biochemical counterpart of plasma membrane microdomains) fraction obtained from BI-1-overexpressing rice cells. Comparative proteomics analysis showed quantitative changes of DRM proteins in BI-1-overexpressing cells. In particular, the protein abundance of FLOTILLIN HOMOLOG (FLOT) and HYPERSENSITIVE-INDUCED REACTION PROTEIN3 (HIR3) markedly decreased in DRM of BI-1-overexpressing cells. Loss-of-function analysis demonstrated that FLOT and HIR3 are required for cell death by oxidative stress and salicylic acid, suggesting that the decreased levels of these proteins directly contribute to the stress-tolerant phenotypes in BI-1-overexpressing rice cells. These findings provide a novel biological implication of plant membrane microdomains in stress-induced cell death, which is negatively modulated by BI-1 overexpression via decreasing the abundance of a set of key proteins involved in cell death.
  AMER SOC PLANT BIOLOGISTS, English, Scientific journal
  DOI：https://doi.org/10.1104/pp.15.00445
  DOI ID：10.1104/pp.15.00445, ISSN：0032-0889, eISSN：1532-2548, ORCID：45646363, Web of Science ID：WOS:000365401000038
• Ethylene Biosynthesis Is Promoted by Very-Long-Chain Fatty Acids during Lysigenous Aerenchyma Formation in Rice Roots.　　　　　　　　　　　　　　　
  Takaki Yamauchi; Katsuhiro Shiono; Minoru Nagano; Aya Fukazawa; Miho Ando; Itsuro Takamure; Hitoshi Mori; Naoko K Nishizawa; Maki Kawai-Yamada; Nobuhiro Tsutsumi; Kiyoaki Kato; Mikio Nakazono
  Plant physiology, Volume：169, Number：1, First page：180, Last page：93, Sep. 2015, [Reviewed], ［International magazine］
  In rice (Oryza sativa) roots, lysigenous aerenchyma, which is created by programmed cell death and lysis of cortical cells, is constitutively formed under aerobic conditions, and its formation is further induced under oxygen-deficient conditions. Ethylene is involved in the induction of aerenchyma formation. reduced culm number1 (rcn1) is a rice mutant in which the gene encoding the ATP-binding cassette transporter RCN1/OsABCG5 is defective. Here, we report that the induction of aerenchyma formation was reduced in roots of rcn1 grown in stagnant deoxygenated nutrient solution (i.e. under stagnant conditions, which mimic oxygen-deficient conditions in waterlogged soils). 1-Aminocyclopropane-1-carboxylic acid synthase (ACS) is a key enzyme in ethylene biosynthesis. Stagnant conditions hardly induced the expression of ACS1 in rcn1 roots, resulting in low ethylene production in the roots. Accumulation of saturated very-long-chain fatty acids (VLCFAs) of 24, 26, and 28 carbons was reduced in rcn1 roots. Exogenously supplied VLCFA (26 carbons) increased the expression level of ACS1 and induced aerenchyma formation in rcn1 roots. Moreover, in rice lines in which the gene encoding a fatty acid elongase, CUT1-LIKE (CUT1L; a homolog of the gene encoding Arabidopsis CUT1, which is required for cuticular wax production), was silenced, both ACS1 expression and aerenchyma formation were reduced. Interestingly, the expression of ACS1, CUT1L, and RCN1/OsABCG5 was induced predominantly in the outer part of roots under stagnant conditions. These results suggest that, in rice under oxygen-deficient conditions, VLCFAs increase ethylene production by promoting 1-aminocyclopropane-1-carboxylic acid biosynthesis in the outer part of roots, which, in turn, induces aerenchyma formation in the root cortex.
  English, Scientific journal
  DOI：https://doi.org/10.1104/pp.15.00106
  DOI ID：10.1104/pp.15.00106, ORCID：45646359, PubMed ID：26036614, PubMed Central ID：PMC4577372, Web of Science ID：WOS:000360930600017
• Effects of water turbulence on variations in cell ultrastructure and metabolism of amino acids in the submersed macrophyte, Elodea nuttallii (Planch.) H. St. John　　　　　　　　　　　　　　　
  K. S. S. Atapaththu; A. Miyagi; K. Atsuzawa; Y. Kaneko; M. Kawai-Yamada; T. Asaeda
  PLANT BIOLOGY, Volume：17, Number：5, First page：997, Last page：1004, Sep. 2015, [Reviewed]
  The interactions between macrophytes and water movement are not yet fully understood, and the causes responsible for the metabolic and ultrastructural variations in plant cells as a consequence of turbulence are largely unknown. In the present study, growth, metabolism and ultrastructural changes were evaluated in the aquatic macrophyte Elodea nuttallii, after exposure to turbulence for 30days. The turbulence was generated with a vertically oscillating horizontal grid. The turbulence reduced plant growth, plasmolysed leaf cells and strengthened cell walls, and plants exposed to turbulence accumulated starch granules in stem chloroplasts. The size of the starch granules increased with the magnitude of the turbulence. Using capillary electrophoresis-mass spectrometry (CE-MS), analysis of the metabolome found metabolite accumulation in response to the turbulence. Asparagine was the dominant amino acid that was concentrated in stressed plants, and organic acids such as citrate, ascorbate, oxalate and -amino butyric acid (GABA) also accumulated in response to turbulence. These results indicate that turbulence caused severe stress that affected plant growth, cell ultrastructure and some metabolic functions of E.nuttallii. Our findings offer insights to explain the effects of water movement on the functions of aquatic plants.
  WILEY-BLACKWELL, English, Scientific journal
  DOI：https://doi.org/10.1111/plb.12346
  DOI ID：10.1111/plb.12346, ISSN：1435-8603, eISSN：1438-8677, ORCID：45646358, Web of Science ID：WOS:000359604800009
• Arabidopsis NAC domain proteins VND-INTERACTING1 and ANAC103 interact with multiple NAC domain proteins　　　　　　　　　　　　　　　
  Masatoshi Yamaguchi; Isura Sumeda Priyadarshana Nagahage; Misato Ohtani; Toshiki Ishikawa; Hirofumi Uchimiya; Maki Kawai-Yamada; Taku Demura
  PLANT BIOTECHNOLOGY, Volume：32, Number：2, First page：119, Last page：U14, Jun. 2015, [Reviewed]
  The Arabidopsis thaliana NAM, ATAF1/2 and CUC2 (NAC) domain transcription factor VND-INTERACTING1 (VNI1) was previously isolated as an interacting factor of VASCULAR-RELATED NAC-DOMAIN PROTEIN7 (VND7), a key regulator of xylem vessel differentiation, in a yeast two-hybrid screening. Here, we characterized VNI1 and its closest homolog, ANAC103, at the molecular level. Both VNI1 and ANAC103 interacted in vitro not only with VND proteins but also with other NAC domain proteins, such as NAC1 and CUC2. A transient expression assay showed that both VNI1 and ANAC103 are transcriptional activators. ANAC103 promoter activity was detected in vascular tissues, as well as in the trichomes, guard cells, and margins of young leaves. These data suggest that VNI1 and ANAC103 promote the differentiation of various types of cells by modulating the transcriptional activities of a wide range of NAC domain transcription factors.
  JAPANESE SOC PLANT CELL & MOLECULAR BIOLOGY, English, Scientific journal
  DOI：https://doi.org/10.5511/plantbiotechnology.15.0208a
  DOI ID：10.5511/plantbiotechnology.15.0208a, ISSN：1342-4580, ORCID：45646357, Web of Science ID：WOS:000356970600002
• The effects of dark incubation on cellular metabolism of the wild type cyanobacterium Synechocystis sp. PCC 6803 and a mutant lacking the transcriptional regulator cyAbrB2.　　　　　　　　　　　　　　　
  Masamitsu Hanai; Yusuke Sato; Atsuko Miyagi; Maki Kawai-Yamada; Kyoko Tanaka; Yasuko Kaneko; Yoshitaka Nishiyama; Yukako Hihara
  Life, Volume：4, Number：4, First page：770, Last page：787, Nov. 2014, [Reviewed], [Invited]
  English, Scientific journal
  DOI：https://doi.org/10.3390/life4040770
  DOI ID：10.3390/life4040770
• Does the Upstream Region Possessing MULE-Like Sequence in Rice Upregulate PsbS1 Gene Expression?　　　　　　　　　　　　　　　
  Mohammed Nuruzzaman; Tatsuo Kanno; Rika Amada; Yoshiki Habu; Ichiro Kasajima; Toshiki Ishikawa; Maki Kawai-Yamada; Hirofumi Uchimiya
  PLOS ONE, Volume：9, Number：9, Sep. 2014, [Reviewed]
  The genomic nucleotide sequences of japonica rice (Sasanishiki and Nipponbare) contained about 2.7-kb unique region at the point of 0.4-kb upstream of the OsPsbS1 gene. In this study, we found that japonica rice with a few exceptions possessing such DNA sequences [denoted to OsMULE-japonica specific sequence (JSS)] is distinct by the presence of Mutator-like-element (MULE). Such sequence was absent in most of indica cultivars and Oryza glaberrima. In OsMULE-JSS1, we noted the presence of possible target site duplication (TSD; CTTTTCCAG) and about 80-bp terminal inverted repeat (TIR) near TSD. We also found the enhancement ofOsPsbS1 mRNA accumulation by intensified light, which was not associated with the DNA methylation status in OsMULE/JSS. In addition, O. rufipogon, possible ancestor of modern rice cultivars was found to compose PsbS gene of either japonica (minor) or indica (major) type. Transient gene expression assay showed that the japonica type promoter elevated a reporter gene activity than indica type.
  PUBLIC LIBRARY SCIENCE, English, Scientific journal
  DOI：https://doi.org/10.1371/journal.pone.0102742
  DOI ID：10.1371/journal.pone.0102742, ISSN：1932-6203, ORCID：45646368, Web of Science ID：WOS:000342685600002
• Effects of NAD kinase 2 overexpression on primary metabolite profiles in rice leaves under elevated carbon dioxide　　　　　　　　　　　　　　　
  Y. Onda; A. Miyagi; K. Takahara; H. Uchimiya; M. Kawai-Yamada
  PLANT BIOLOGY, Volume：16, Number：4, First page：819, Last page：824, Jul. 2014, [Reviewed]
  The concentration of carbon dioxide (CO2) in the atmosphere is projected to double by the end of the 21st century. In C-3 plants, elevated CO2 concentrations promote photosynthesis but inhibit the assimilation of nitrate into organic nitrogen compounds. Several steps of nitrate assimilation depend on the availability of ATP and sources of reducing power, such as nicotinamide adenine dinucleotide phosphate (NADPH). Plastid-localised NAD kinase 2 (NADK2) plays key roles in increasing the ATP/ADP and NADP(H)/NAD(H) ratios. Here we examined the effects of NADK2 overexpression on primary metabolism in rice (Oryza sativa) leaves in response to elevated CO2. By using capillary electrophoresis mass spectrometry, we showed that the primary metabolite profile of NADK2-overexpressing plants clearly differed from that of wild-type plants under ambient and elevated CO2. In NADK(2)-overexpressing leaves, expression of the genes encoding glutamine synthetase and glutamate synthase was up-regulated, and the levels of Asn, Gln, Arg, and Lys increased in response to elevated CO2. The present study suggests that overexpression of NADK2 promotes the biosynthesis of nitrogen-rich amino acids under elevated CO2.
  WILEY-BLACKWELL, English, Scientific journal
  DOI：https://doi.org/10.1111/plb.12131
  DOI ID：10.1111/plb.12131, ISSN：1435-8603, eISSN：1438-8677, ORCID：45646369, Web of Science ID：WOS:000337613000016
• Arabidopsis Bax inhibitor-1 promotes sphingolipid synthesis during cold stress by interacting with ceramide-modifying enzymes　　　　　　　　　　　　　　　
  Minoru Nagano; Toshiki Ishikawa; Yoshie Ogawa; Mitsuru Iwabuchi; Akari Nakasone; Ko Shimamoto; Hirofumi Uchimiya; Maki Kawai-Yamada
  PLANTA, Volume：240, Number：1, First page：77, Last page：89, Jul. 2014, [Reviewed]
  Bax inhibitor-1 (BI-1) is a widely conserved cell death suppressor localized in the endoplasmic reticulum membrane. Our previous results revealed that Arabidopsis BI-1 (AtBI-1) interacts with not only Arabidopsis cytochrome b (5) (Cb5), an electron transfer protein, but also a Cb5-like domain (Cb5LD)-containing protein, Saccharomyces cerevisiae fatty acid 2-hydroxylase 1, which 2-hydroxylates sphingolipid fatty acids. We have now found that AtBI-1 binds Arabidopsis sphingolipid Delta 8 long-chain base (LCB) desaturases AtSLD1 and AtSLD2, which are Cb5LD-containing proteins. The expression of both AtBI-1 and AtSLD1 was increased by cold exposure. However, different phenotypes were observed in response to cold treatment between an atbi-1 mutant and a sld1sld2 double mutant. To elucidate the reasons behind the difference, we analyzed sphingolipids and found that unsaturated LCBs in atbi-1 were not altered compared to wild type, whereas almost all LCBs in sld1sld2 were saturated, suggesting that AtBI-1 may not be necessary for the desaturation of LCBs. On the other hand, the sphingolipid content in wild type increased in response to low temperature, whereas total sphingolipid levels in atbi-1 were unaltered. In addition, the ceramide-modifying enzymes AtFAH1, sphingolipid base hydroxylase 2 (AtSBH2), acyl lipid desaturase 2 (AtADS2) and AtSLD1 were highly expressed under cold stress, and all are likely to be related to AtBI-1 function. These findings suggest that AtBI-1 contributes to synthesis of sphingolipids during cold stress by interacting with AtSLD1, AtFAH1, AtSBH2 and AtADS2.
  SPRINGER, English, Scientific journal
  DOI：https://doi.org/10.1007/s00425-014-2065-7
  DOI ID：10.1007/s00425-014-2065-7, ISSN：0032-0935, eISSN：1432-2048, ORCID：45646364, Web of Science ID：WOS:000338318300005
• Development of an LC-MS/MS Method for the Analysis of Free Sphingoid Bases Using 4-Fluoro-7-nitrobenzofurazan (NBD-F)　　　　　　　　　　　　　　　
  Toshiki Ishikawa; Hiroyuki Imai; Maki Kawai-Yamada
  LIPIDS, Volume：49, Number：3, First page：295, Last page：304, Mar. 2014, [Reviewed]
  The molecular species of sphingoid bases were tagged with the fluorescent amino group reagent, 4-fluoro-7-nitrobenzofurazan (NBD-F). The NBD-sphingoid bases were analyzed by a highly selective and sensitive liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) technique capable of reliable detection of several fmol of the derivatives. Lipid extracts from plant samples were derivatized with NBD-F, and all nine species of free sphingoid bases present in plant sphingolipids were separated and quantified for the first time; a complete baseline resolution was achieved for cis-8 and trans-8 isomers of sphingoid bases by reversed phase HPLC on a C-18 column. The extraction and derivatization procedures and LC-MS/MS method can facilitate the progress of the studies for seeking the active components of sphingoid bases species in response to biological challenges.
  SPRINGER HEIDELBERG, English, Scientific journal
  DOI：https://doi.org/10.1007/s11745-013-3871-6
  DOI ID：10.1007/s11745-013-3871-6, ISSN：0024-4201, eISSN：1558-9307, ORCID：45646367, Web of Science ID：WOS:000332665600009
• Culture temperature affects gene expression and metabolic pathways in the 2-methylisoborneol-producing cyanobacterium Pseudanabaena galeata　　　　　　　　　　　　　　　
  Masayuki Kakimoto; Toshiki Ishikawa; Atsuko Miyagi; Kazuaki Saito; Motonobu Miyazaki; Takashi Asaeda; Masatoshi Yamaguchi; Hirofumi Uchimiya; Maki Kawai-Yamada
  JOURNAL OF PLANT PHYSIOLOGY, Volume：171, Number：3-4, First page：292, Last page：300, Feb. 2014, [Reviewed]
  A volatile metabolite, 2-methylisoborneol (2-MIB), causes an unpleasant taste and odor in tap water. Some filamentous cyanobacteria produce 2-MIB via a two-step biosynthetic pathway: methylation of geranyl diphosphate (GPP) by methyl transferase (GPPMT), followed by the cyclization of methyl-GPP by monoterpene cyclase (MIBS). We isolated the genes encoding GPPMT and MIBS from Pseudanabaena galeata, a filamentous cyanobacterium known to be a major causal organism of 2-MIB production in Japanese lakes. The predicted amino acid sequence showed high similarity with that of Pseudanabaena limnetica (96% identity in GPPMT and 97% identity in MIBS). P. galeata was cultured at different temperatures to examine the effect of growth conditions on the production of 2-MIB and major metabolites. Gas chromatograph-mass spectrometry (GC-MS) measurements showed higher accumulation of 2-MIB at 30 degrees C than at 4 degrees C or 20 degrees C after 24 h of culture. Real-time-RT PCR analysis showed that the expression levels of the genes encoding GPPMT and MIBS decreased at 4 degrees C and increased at 30 degrees C, compared with at 20 degrees C. Furthermore, metabolite analysis showed dramatic changes in primary metabolite concentrations in cyanobacteria grown at different temperatures. The data indicate that changes in carbon flow in the TCA cycle affect 2-MIB biosynthesis at higher temperatures. (C) 2013 Elsevier GmbH. All rights reserved.
  ELSEVIER GMBH, URBAN & FISCHER VERLAG, English, Scientific journal
  DOI：https://doi.org/10.1016/j.jplph.2013.09.005
  DOI ID：10.1016/j.jplph.2013.09.005, ISSN：0176-1617, ORCID：45646366, Web of Science ID：WOS:000332052200013
• Advanced LC-MS/MS techniques dissecting diverse isomers of plant sphingolipid species.　　　　　　　　　　　　　　　
  Ishikawa T; Yanagawa D; Kawai-Yamada M; Imai H
  J. Anal. Bioanal. Tech., Volume：S5, First page：7, 2014, [Reviewed]
  English, Scientific journal
  DOI：https://doi.org/10.4172/2155-9872.S5-007
  DOI ID：10.4172/2155-9872.S5-007
• Plastidic protein Cdf1 is essential in Arabidopsis embryogenesis　　　　　　　　　　　　　　　
  Maki Kawai-Yamada; Minoru Nagano; Masayuki Kakimoto; Hirofumi Uchimiya
  PLANTA, Volume：239, Number：1, First page：39, Last page：46, Jan. 2014, [Reviewed]
  Arabidopsis cell growth defect factor-1 (Cdf1 in yeast, At5g23040) was originally isolated as a cell growth suppressor of yeast from genetic screening. To investigate the in vivo role of Cdf1 in plants, a T-DNA insertion line was analyzed. A homozygous T-DNA insertion mutant (cdf1/cdf1) was embryo lethal and showed arrested embryogenesis at the globular stage. The Cdf1 protein, when fused with green fluorescent protein, was localized to the plastid in stomatal guard cells and mesophyll cells. A promoter-beta-glucuronidase assay found expression of Cdf1 in the early heart stage of embryogenesis, suggesting that Cdf1 was essential for Arabidopsis embryogenesis during the transition of the embryo from the globular to heart stage.
  SPRINGER, English, Scientific journal
  DOI：https://doi.org/10.1007/s00425-013-1966-1
  DOI ID：10.1007/s00425-013-1966-1, ISSN：0032-0935, eISSN：1432-2048, ORCID：45646370, Web of Science ID：WOS:000329240700003
• Arabidopsis glycerol-3-phosphate permease 4 is localized in the plastids and involved in the accumulation of seed oil　　　　　　　　　　　　　　　
  Hiromitsu Kawai; Toshiki Ishikawa; Toshiaki Mitsui; Shin Kore-eda; Maki Kawai-Yamada; Jun-ichi Ohnishi
  PLANT BIOTECHNOLOGY, Volume：31, Number：2, First page：159, Last page：U80, 2014, [Reviewed]
  In plant cells, glycerol 3-phosphate (G3P) is apparently able to permeate the plastid envelope, but no specific transporter has been characterized so far. The Arabidopsis five G3Pp proteins have been predicted as putative G3P permeases because of their high homologies with the prokaryotic G3P/phosphate antiporter GlpT. In the present study, G3Pp4 was characterized in detail utilizing reverse genetic approaches. Promoter analysis using GUS expression revealed that G3Pp4 was expressed strongly throughout the embryos during late developmental stages, and the seed lipid contents decreased in two g3pp4 knockout mutants. An enhanced yellow fluorescent protein-fused G3Pp4 was localized in the plastids, functioned physiologically in A. thaliana, and had G3P-transport activity in E. coli. These results suggest that Arabidopsis G3Pp4 is a plastid envelope-localized G3P transporter and involved in accumulation of storage lipids in late embryogenesis.
  JAPANESE SOC PLANT CELL & MOLECULAR BIOLOGY, English, Scientific journal
  DOI：https://doi.org/10.5511/plantbiotechnology.14.0222a
  DOI ID：10.5511/plantbiotechnology.14.0222a, ISSN：1342-4580, ORCID：45646365, Web of Science ID：WOS:000339501900009
• Metabolic alterations in leaves of oxalate-rich plant Rumex obtusifolius L. irradiated by gamma rays　　　　　　　　　　　　　　　
  Sayaka Kitano; Atsuko Miyagi; Yutaka Oono; Yoshihiro Hase; Issay Narumi; Masatoshi Yamaguchi; Hirofumi Uchimiya; Maki Kawai-Yamada
  Metabolomics, Volume：11, Number：1, First page：134, Last page：142, 2014, [Reviewed]
  © 2014, Springer Science+Business Media New York. Oxalate in some plants is toxic to vertebrates and causes kidney failure. In the present study, we investigated on the metabolic effectiveness of gamma ray irradiation to seeds of Rumex obtusifolius, which are known to accumulate high level of soluble oxalate, to lower oxalate accumulation in leaves. Reduced rate of germination, discoloration of cotyledons, and deformed true leaves were observed by elevated irradiation. Metabolome analysis of primary metabolites using capillary electrophoresis–mass spectrometry showed a decrease in oxalate contents in the leaves of plants from gamma ray-irradiated seeds. Moreover, organic acids such as malate and 2-oxoglutarate also decreased, whereas amino acids such as glutamate and glutamine increased. These results indicated that seed irradiation by gamma rays leads to dynamic changes in metabolic pathways as well as plant growth/development.
  Scientific journal
  DOI：https://doi.org/10.1007/s11306-014-0684-4
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84939895666&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=84939895666&origin=inward
  DOI ID：10.1007/s11306-014-0684-4, ISSN：1573-3882, eISSN：1573-3890, ORCID：45646362, SCOPUS ID：84939895666, Web of Science ID：WOS:000348343300013
• Rapid Induction of Lipid Droplets in Chlamydomonas reinhardtii and Chlorella vulgaris by Brefeldin A　　　　　　　　　　　　　　　
  Sangwoo Kim; Hanul Kim; Donghwi Ko; Yasuyo Yamaoka; Masumi Otsuru; Maki Kawai-Yamada; Toshiki Ishikawa; Hee-Mock Oh; Ikuo Nishida; Yonghua Li-Beisson; Youngsook Lee
  PLOS ONE, Volume：8, Number：12, Dec. 2013, [Reviewed]
  Algal lipids are the focus of intensive research because they are potential sources of biodiesel. However, most algae produce neutral lipids only under stress conditions. Here, we report that treatment with Brefeldin A (BFA), a chemical inducer of ER stress, rapidly triggers lipid droplet (LD) formation in two different microalgal species, Chlamydomonas reinhardtii and Chlorella vulgaris. LD staining using Nile red revealed that BFA-treated algal cells exhibited many more fluorescent bodies than control cells. Lipid analyses based on thin layer chromatography and gas chromatography revealed that the additional lipids formed upon BFA treatment were mainly triacylglycerols (TAGs). The increase in TAG accumulation was accompanied by a decrease in the betaine lipid diacylglyceryl N,N,N-trimethylhomoserine (DGTS), a major component of the extraplastidic membrane lipids in Chlamydomonas, suggesting that at least some of the TAGs were assembled from the degradation products of membrane lipids. Interestingly, BFA induced TAG accumulation in the Chlamydomonas cells regardless of the presence or absence of an acetate or nitrogen source in the medium. This effect of BFA in Chlamydomonas cells seems to be due to BFA-induced ER stress, as supported by the induction of three homologs of ER stress marker genes by the drug. Together, these results suggest that ER stress rapidly triggers TAG accumulation in two green microalgae, C. reinhardtii and C. vulgaris. A further investigation of the link between ER stress and TAG synthesis may yield an efficient means of producing biofuel from algae.
  PUBLIC LIBRARY SCIENCE, English, Scientific journal
  DOI：https://doi.org/10.1371/journal.pone.0081978
  DOI ID：10.1371/journal.pone.0081978, ISSN：1932-6203, ORCID：45646376, Web of Science ID：WOS:000328734200021
• Metabolome analysis of food-chain between plants and insects　　　　　　　　　　　　　　　
  Atsuko Miyagi; Maki Kawai-Yamada; Minori Uchimiya; Noriyuki Ojima; Koichi Suzuki; Hirofumi Uchimiya
  METABOLOMICS, Volume：9, Number：6, First page：1254, Last page：1261, Dec. 2013, [Reviewed]
  Evolution has shown the co-dependency between host plants and predators (insects), especially inevitable dependency of predators on plant biomass for securing their energy sources. It was postulated that NAD(+) source used for major energy producing pathway is the glycerol-3-phosphate shuttle in insects. Using high throughput metabolomics approach, we found that larva of leaf beetle (Gastrophysa atrocyanea), which feed oxalate-rich plants (Rumex obtusifolius), possessed a unique mechanism for accumulating unusually high amounts of lactate. Similarly, larva of butterfly (Papilio machaon) fed with fennel (Foeniculum vulgare) accumulated lactate. Same butterfly also showed the elevated level of glycerol-3-phosphate equivalent to lactate. These evidences provide new insights into the mechanism underlying metabolite alteration between host plants and insect herbivores.
  SPRINGER, English, Scientific journal
  DOI：https://doi.org/10.1007/s11306-013-0542-9
  DOI ID：10.1007/s11306-013-0542-9, ISSN：1573-3882, eISSN：1573-3890, ORCID：45646374, Web of Science ID：WOS:000326926700012
• Deletion of the Transcriptional Regulator cyAbrB2 Deregulates Primary Carbon Metabolism in Synechocystis sp PCC 6803　　　　　　　　　　　　　　　
  Yuki Kaniya; Ayumi Kizawa; Atsuko Miyagi; Maki Kawai-Yamada; Hirofumi Uchimiya; Yasuko Kaneko; Yoshikata Nishiyama; Yukako Hihara
  PLANT PHYSIOLOGY, Volume：162, Number：2, First page：1153, Last page：1163, Jun. 2013, [Reviewed]
  cyAbrB is a transcriptional regulator unique to and highly conserved among cyanobacterial species. A gene-disrupted mutant of cyabrB2 (sll0822) in Synechocystis sp. PCC 6803 exhibited severe growth inhibition and abnormal accumulation of glycogen granules within cells under photomixotrophic conditions. Within 6 h after the shift to photomixotrophic conditions, sodium bicarbonate-dependent oxygen evolution activity markedly declined in the Delta cyabrB2 mutant, but the decrease in methyl viologen-dependent electron transport activity was much smaller, indicating inhibition in carbon dioxide fixation. Decreases in the transcript levels of several genes related to sugar catabolism, carbon dioxide fixation, and nitrogen metabolism were also observed within 6 h. Metabolome analysis by capillary electrophoresis mass spectrometry revealed that several metabolites accumulated differently in the wild-type and mutant strains. For example, the amounts of pyruvate and 2-oxoglutarate (2OG) were significantly lower in the mutant than in the wild type, irrespective of trophic conditions. The growth rate of the Delta cyabrB2 mutant was restored to a level comparable to that under photoautotrophic conditions by addition of 2OG to the growth medium under photomixotrophic conditions. Activities of various metabolic processes, including carbon dioxide fixation, respiration, and nitrogen assimilation, seemed to be enhanced by 2OG addition. These observations suggest that cyAbrB2 is essential for the active transcription of genes related to carbon and nitrogen metabolism upon a shift to photomixotrophic conditions. Deletion of cyAbrB2 is likely to deregulate the partition of carbon between storage forms and soluble forms used for biosynthetic purposes. This disorder may cause inactivation of cellular metabolism, excess accumulation of reducing equivalents, and subsequent loss of viability under photomixotrophic conditions.
  AMER SOC PLANT BIOLOGISTS, English, Scientific journal
  DOI：https://doi.org/10.1104/pp.113.218784
  DOI ID：10.1104/pp.113.218784, ISSN：0032-0889, ORCID：45646372, Web of Science ID：WOS:000319819900047
• An antagonist treatment in combination with tracer experiments revealed isocitrate pathway dominant to oxalate biosynthesis in Rumex obtusifolius L.　　　　　　　　　　　　　　　
  Atsuko Miyagi; Minori Uchimiya; Maki Kawai-Yamada; Hirofumi Uchimiya
  METABOLOMICS, Volume：9, Number：3, First page：590, Last page：598, Jun. 2013, [Reviewed]
  Oxalate accumulates in leaves of certain plants such as Rumex species (Polygonaceae). Oxalate plays important roles in defense to predator, detoxification of metallic ions, and in hydrogen peroxide formation upon wounding/senescence. However, biosynthetic pathways of soluble oxalate are largely unknown. In the present study we analysed Rumex obtusifolius L. treated with itaconate (an antagonist to isocitrate). Comprehensive metabolome analysis using capillary electrophoresis-mass spectrometry showed that oxalate content of "new leaves" was notably down-regulated by itaconate, as opposed to the accumulation of citrate. The (CO2)-C-13 feeding experiment revealed that oxalate accumulation in new leaves was affected by citrate translocation from stems. The results suggested that excess oxalate in new leaves of R. obtusifolius was synthesized primarily via the isocitrate pathway utilizing citrate delivered from stems.
  SPRINGER, English, Scientific journal
  DOI：https://doi.org/10.1007/s11306-012-0486-5
  DOI ID：10.1007/s11306-012-0486-5, ISSN：1573-3882, ORCID：45646371, Web of Science ID：WOS:000318905100007
• NAD⁺ accumulation as a metabolic off switch for orthodox pollen.　　　　　　　　　　　　　　　
  Hashida SN; Kawai-Yamada M; Uchimiya H
  Plant signaling & behavior, Volume：8, Number：5, First page：e23937, May 2013, [Reviewed]
  DOI：https://doi.org/10.4161/psb.23937
  DOI ID：10.4161/psb.23937, ISSN：1559-2316, PubMed ID：23428890
• Accelerated NAD metabolism reveals the essential role of NADH/NAD ratio on onset of senescence and carbon stock redistribution in Arabidopsis
  HASHIDA Shin‐nosuke; KITAZAKI Kazuyoshi; SHOJI Kazuhiro; GOTO Fumiyuki; YOSHIHARA Toshihiro; KAWAI‐YAMADA Maki; UCHIMIYA Hirofumi
  日本植物生理学会年会要旨集, Volume：54th, First page：244, Mar. 2013
  English
  J-Global ID：201302281097335366
• Impact of aluminium stress on oxalate and other metabolites in Rumex obtusifolius　　　　　　　　　　　　　　　
  A. Miyagi; M. Uchimiya; M. Kawai-Yamada; H. Uchimiya
  WEED RESEARCH, Volume：53, Number：1, First page：30, Last page：41, Feb. 2013, [Reviewed]
  To understand alterations of oxalate and other metabolite levels induced by aluminium ion (Al3+) stress in Rumex plants, we measured the metabolites in R. obtusifolius using the capillary electrophoresismass spectrometry. Oxalate and its precursors (isocitrate and citrate) accumulated in leaves of R. obtusifolius after the Al3+ treatment at pH 4.5. Such increase was not observed under the acidic condition (pH 4.5) without Al3+. Principal component analysis showed organ-specific changes in metabolite levels in R. obtusifolius by the Al3+ treatment. Highly positive correlations between oxalate and its precursors were revealed by hierarchical clustering and correlation analyses. An increase in oxalate content was consistently observed for three Rumex species (R. obtusifolius, R. crispus and R. japonicus) grown in the presence of Al3+. On the other hand, multivariate analyses revealed the differential alterations of other metabolite levels between R. obtusifolius and the other two Rumex species.
  WILEY-BLACKWELL, English, Scientific journal
  DOI：https://doi.org/10.1111/j.1365-3180.2012.00949.x
  DOI ID：10.1111/j.1365-3180.2012.00949.x, ISSN：0043-1737, ORCID：45646373, Web of Science ID：WOS:000312996900004
• Effect of gamma ray irradiation on Rumex obtusifolius L.　　　　　　　　　　　　　　　
  Sayaka Kitano; Atsuko Miyagi; Yutaka Oono; Yoshihiro Hase; Issay Narumi; Hirofumi Uchimiya; Maki Kawai-Yamada
  First page：101, Jan. 2013
• The role of plant bax inhibitor-1 in suppressing H2O 2-induced cell death　　　　　　　　　　　　　　　
  Toshiki Ishikawa; Hirofumi Uchimiya; Maki Kawai-Yamada
  Methods in Enzymology, Volume：527, First page：239, Last page：256, 2013, [Reviewed]
  Hydrogen peroxide (H2O2) is known to be a typical endogenous signaling molecule that triggers programmed cell death in plants and metazoan. In this respect, they seem to share the mechanism of cell death caused by H2O2 and other reactive oxygen species (ROS). Bax inhibitor-1 (BI-1) is a well-conserved protein in plants and animals that serves as the inhibitor of mammalian proapoptotic proteins as well as plant ROS-induced cell death. As a target of H2O2, mitochondrion is considered to be an organelle of the primary ROS generation and perception. Thus, analysis of mitochondrial behavior in relation to functional roles of regulatory proteins (e.g., BI-1) will lead us to understand the core mechanisms of cell death regulation conserved in eukaryotes. In this chapter, we first introduce techniques of analyzing H2O2- (and ROS-) mediated changes in mitochondrial behavior. Next, we describe our understanding of the functions of plant BI-1 in regulation of ROS-induced cell death, with a technical basis for assessment of tolerance to ROS-mediated cell death in model plant systems. © 2013 Elsevier Inc.
  English, Scientific journal
  DOI：https://doi.org/10.1016/B978-0-12-405882-8.00013-1
  DOI ID：10.1016/B978-0-12-405882-8.00013-1, ISSN：0076-6879, ORCID：45646377, PubMed ID：23830635, SCOPUS ID：84879857652, Web of Science ID：WOS:000322846400014
• NAD(+) Accumulation during Pollen Maturation in Arabidopsis Regulating Onset of Germination　　　　　　　　　　　　　　　
  Shin-nosuke Hashida; Hideyuki Takahashi; Kentaro Takahara; Maki Kawai-Yamada; Kazuyoshi Kitazaki; Kazuhiro Shoji; Fumiyuki Goto; Toshihiro Yoshihara; Hirofumi Uchimiya
  MOLECULAR PLANT, Volume：6, Number：1, First page：216, Last page：225, Jan. 2013, [Reviewed]
  Although the nicotinamide nucleotides NAD(H) and NADP(H) are essential for various metabolic reactions that play major roles in maintenance of cellular homeostasis, the significance of NAD biosynthesis is not well understood. Here, we investigated the dynamics of pollen nicotinamide nucleotides in response to imbibition, a representative germination cue. Metabolic analysis with capillary electrophoresis electrospray ionization mass spectrometry revealed that excess amount of NAD(+) is accumulated in freshly harvested dry pollen, whereas it dramatically decreased immediately after contact with water. Importantly, excess of NAD(+) impaired pollen tube growth. Moreover, NAD(+) accumulation was retained after pollen was imbibed in the presence of NAD(+)-consuming reaction inhibitors and pollen germination was greatly retarded. Pollen deficient in the nicotinate/nicotinamide mononucleotide adenyltransferase (NMNAT) gene, encoding a key enzyme in NAD biosynthesis, and a lack of NAD(+) accumulation in the gametophyte, showed precocious pollen tube germination inside the anther locule and vigorous tube growth under high-humidity conditions. Hence, the accumulation of excess NAD(+) is not essential for pollen germination, but instead participates in regulating the timing of germination onset. These results indicate that NAD(+) accumulation acts to negatively regulate germination and a decrease in NAD(+) plays an important role in metabolic state transition.
  OXFORD UNIV PRESS, English, Scientific journal
  DOI：https://doi.org/10.1093/mp/sss071
  DOI ID：10.1093/mp/sss071, ISSN：1674-2052, ORCID：45646375, Web of Science ID：WOS:000314117100022
• SMALL ACICIC PROTEIN1 Acts with RUB Modification Components, the COP9 Signalosome and AXR1 to Regulate Growth and Development of Arabidopsis (vol 160, pg 93, 2012)　　　　　　　　　　　　　　　
  A. Nakasone; M. Fujiwara; Y. Fukao; K. K. Biswas; A. Rahman; M. Kawai-Yamada; Narumi, I; H. Uchimiya; Y. Oono
  PLANT PHYSIOLOGY, Volume：160, Number：3, First page：1674, Last page：1674, Nov. 2012, [Reviewed]
  AMER SOC PLANT BIOLOGISTS, English
  DOI：https://doi.org/10.1104/pp.112.900448
  DOI ID：10.1104/pp.112.900448, ISSN：0032-0889, ORCID：45646378, Web of Science ID：WOS:000310584200039
• SMALL ACIDIC PROTEIN1 acts with RUB modification components, the COP9 signalosome, and AXR1 to regulate growth and development of Arabidopsis.　　　　　　　　　　　　　　　
  Akari Nakasone; Masayuki Fujiwara; Yoichiro Fukao; Kamal Kanti Biswas; Abidur Rahman; Maki Kawai-Yamada; Issay Narumi; Hirofumi Uchimiya; Yutaka Oono
  Plant physiology, Volume：160, Number：1, First page：93, Last page：105, Sep. 2012, [Reviewed], ［International magazine］
  Previously, a dysfunction of the SMALL ACIDIC PROTEIN1 (SMAP1) gene was identified as the cause of the anti-auxin resistant1 (aar1) mutant of Arabidopsis (Arabidopsis thaliana). SMAP1 is involved in the response pathway of synthetic auxin, 2,4-dichlorophenoxyacetic acid, and functions upstream of the auxin/indole-3-acetic acid protein degradation step in auxin signaling. However, the exact mechanism by which SMAP1 functions in auxin signaling remains unknown. Here, we demonstrate that SMAP1 is required for normal plant growth and development and the root response to indole-3-acetic acid or methyl jasmonate in the auxin resistant1 (axr1) mutation background. Deletion analysis and green fluorescent protein/glutathione S-transferase pull-down assays showed that SMAP1 physically interacts with the CONSTITUTIVE PHOTOMORPHOGENIC9 SIGNALOSOME (CSN) via the SMAP1 F/D region. The extremely dwarf phenotype of the aar1-1 csn5a-1 double mutant confirms the functional role of SMAP1 in plant growth and development under limiting CSN functionality. Our findings suggest that SMAP1 is involved in the auxin response and possibly in other cullin-RING ubiquitin ligase-regulated signaling processes via its interaction with components associated with RELATED TO UBIQUITIN modification.
  English, Scientific journal
  DOI：https://doi.org/10.1104/pp.111.188409
  DOI ID：10.1104/pp.111.188409, ORCID：45646379, PubMed ID：22576848, PubMed Central ID：PMC3440233, Web of Science ID：WOS:000308675100011
• Arabidopsis Sphingolipid Fatty Acid 2-Hydroxylases (AtFAH1 and AtFAH2) Are Functionally Differentiated in Fatty Acid 2-Hydroxylation and Stress Responses　　　　　　　　　　　　　　　
  Nagano, M; Takahara, K; Fujimoto, M; Tsutsumi, N; Uchimiya, H; Kawai-Yamada, M
  PLANT PHYSIOLOGY, Volume：159, Number：3, First page：1138, Last page：1148, Jul. 2012, [Reviewed]
  2-Hydroxy fatty acids (2-HFAs) are predominantly present in sphingolipids and have important physicochemical and physiological functions in eukaryotic cells. Recent studies from our group demonstrated that sphingolipid fatty acid 2-hydroxylase (FAH) is required for the function of Arabidopsis (Arabidopsis thaliana) Bax inhibitor-1 (AtBI-1), which is an endoplasmic reticulum membrane-localized cell death suppressor. However, little is known about the function of two Arabidopsis FAH homologs (AtFAH1 and AtFAH2), and it remains unclear whether 2-HFAs participate in cell death regulation. In this study, we found that both AtFAH1 and AtFAH2 had FAH activity, and the interaction with Arabidopsis cytochrome b(5) was needed for the sufficient activity. 2-HFA analysis of AtFAH1 knockdown lines and atfah2 mutant showed that AtFAH1 mainly 2-hydroxylated very-long-chain fatty acid (VLCFA), whereas AtFAH2 selectively 2-hydroxylated palmitic acid in Arabidopsis. In addition, 2-HFAs were related to resistance to oxidative stress, and AtFAH1 or 2-hydroxy VLCFA showed particularly strong responses to oxidative stress. Furthermore, AtFAH1 interacted with AtBI-1 via cytochrome b(5) more preferentially than AtFAH2. Our results suggest that AtFAH1 and AtFAH2 are functionally different FAHs, and that AtFAH1 or 2-hydroxy VLCFA is a key factor in AtBI-1-mediated cell death suppression.
  AMER SOC PLANT BIOLOGISTS, English, Scientific journal
  DOI：https://doi.org/10.1104/pp.112.199547
  DOI ID：10.1104/pp.112.199547, ISSN：0032-0889, eISSN：1532-2548, Web of Science ID：WOS:000305958000022
• Gsp1 triggers the sexual developmental program including inheritance of chloroplast DNA and mitochondrial DNA in Chlamydomonas reinhardtii.　　　　　　　　　　　　　　　
  Nishimura Y; Shikanai T; Nakamura S; Kawai-Yamada M; Uchimiya H
  The Plant cell, Volume：24, Number：6, First page：2401, Last page：2414, Jun. 2012, [Reviewed]
  DOI：https://doi.org/10.1105/tpc.112.097865
  DOI ID：10.1105/tpc.112.097865, ISSN：1040-4651, PubMed ID：22715041
• Nitrate addition alleviates ammonium toxicity without lessening ammonium accumulation, organic acid depletion and inorganic cation depletion in Arabidopsis thaliana shoots.　　　　　　　　　　　　　　　
  Hachiya T; Watanabe CK; Fujimoto M; Ishikawa T; Takahara K; Kawai-Yamada M; Uchimiya H; Uesono Y; Terashima I; Noguchi K
  Plant & cell physiology, Volume：53, Number：3, First page：577, Last page：591, Mar. 2012, [Reviewed]
  Oxford University Press, English
  DOI ID：10.1093/pcp/pcs012, ISSN：0032-0781, CiNii Articles ID：10030309550, CiNii Books ID：AA0077511X, PubMed ID：22318863, Web of Science ID：WOS:000301359500008
• Plant sphingolipid fatty acid 2-hydroxylases have unique characters unlike their animal and fungus counterparts　　　　　　　　　　　　　　　
  Minoru Nagano; Hirofumi Uchimiya; Maki Kawai-Yamada
  Plant Signaling and Behavior, Volume：7, Number：11, 2012, [Reviewed]
  2-Hydroxy fatty acids mainly contained in sphingolipids are synthesized by a sphingolipid fatty acid 2-hydroxylase (FAH). Recently, two FAH homologs in Arabidopsis thaliana (AtFAH1 and AtFAH2), without any cytochrome b5(Cb5)-like domains, which are essential for the function of Saccharomyces cerevisiae and mammalian FAH, were identified and both AtFAHs were shown to be activated by the interaction with Cb5. In this study, we compared FAHs of various plants, animals and fungi. Interestingly, only plants had two FAH homologs and none of plant FAHs had any Cb5-like domains. In addition, we showed from the interaction and expression analyses that AtFAHs interacted with multiple Cb5s probably in various tissues. Thus, plant FAHs may have evolved unlike animal and fungus FAHs. © 2012 Landes Bioscience.
  Landes Bioscience, English, Scientific journal
  DOI：https://doi.org/10.4161/psb.21825
  DOI ID：10.4161/psb.21825, ISSN：1559-2324, PubMed ID：22918503, SCOPUS ID：84868513722
• Fate of C-13 in metabolic pathways and effects of high CO2 on the alteration of metabolites in Rumex obtusifolius L.　　　　　　　　　　　　　　　
  Atsuko Miyagi; Kentaro Takahara; Ichiro Kasajima; Hideyuki Takahashi; Maki Kawai-Yamada; Hirofumi Uchimiya
  METABOLOMICS, Volume：7, Number：4, First page：524, Last page：535, Dec. 2011, [Reviewed]
  In present study, in vivo turn-over of (CO2)-C-13 to organic acids such as oxalate and citrate in Rumex obtusifolius L. was explored. Conversion of fixed carbon to oxalate was studies using "new leaves", i.e., leaves removed from 2-month-old-plants grown under different environmental conditions. Collected new leaves and stems were subjected to metabolomic analyses using capillary electrophoresis mass spectrometry. The results showed the mobilization of metabolites from stems to new leaves, where active TCA cycle and oxalate pathways occurred. The C-13 labeling experiments also indicated that these pathways are active in new leaves. Subsequently, we compared the effects of high carbon dioxide level (1000 ppm) and nutrients (Hoagland's formulation) on the metabolite accumulation in R. obtusifolius. Data analysed by both principal component and hierarchical clustering analyses revealed significant changes in metabolite accumulation. The accumulation of most abundant metabolite oxalate in leaves was affected by both high CO2 as the carbon source and nutrients. We suggest that the common weed R. obtusifolius may proliferate in cultivated lands under high CO2 level, a potential cause of global warming.
  SPRINGER, English, Scientific journal
  DOI：https://doi.org/10.1007/s11306-010-0272-1
  DOI ID：10.1007/s11306-010-0272-1, ISSN：1573-3882, ORCID：45646382, Web of Science ID：WOS:000295991900006
• Morphological classification of plant cell deaths　　　　　　　　　　　　　　　
  W. G. van Doorn; E. P. Beers; J. L. Dangl; V. E. Franklin-Tong; P. Gallois; I. Hara-Nishimura; A. M. Jones; M. Kawai-Yamada; E. Lam; J. Mundy; L. A. J. Mur; M. Petersen; A. Smertenko; M. Taliansky; F. Van Breusegem; T. Wolpert; E. Woltering; B. Zhivotovsky; P. V. Bozhkov
  CELL DEATH AND DIFFERENTIATION, Volume：18, Number：8, First page：1241, Last page：1246, Aug. 2011, [Reviewed]
  Programmed cell death (PCD) is an integral part of plant development and of responses to abiotic stress or pathogens. Although the morphology of plant PCD is, in some cases, well characterised and molecular mechanisms controlling plant PCD are beginning to emerge, there is still confusion about the classification of PCD in plants. Here we suggest a classification based on morphological criteria. According to this classification, the use of the term 'apoptosis' is not justified in plants, but at least two classes of PCD can be distinguished: vacuolar cell death and necrosis. During vacuolar cell death, the cell contents are removed by a combination of autophagy-like process and release of hydrolases from collapsed lytic vacuoles. Necrosis is characterised by early rupture of the plasma membrane, shrinkage of the protoplast and absence of vacuolar cell death features. Vacuolar cell death is common during tissue and organ formation and elimination, whereas necrosis is typically found under abiotic stress. Some examples of plant PCD cannot be ascribed to either major class and are therefore classified as separate modalities. These are PCD associated with the hypersensitive response to biotrophic pathogens, which can express features of both necrosis and vacuolar cell death, PCD in starchy cereal endosperm and during self-incompatibility. The present classification is not static, but will be subject to further revision, especially when specific biochemical pathways are better defined. Cell Death and Differentiation (2011) 18, 1241-1246; doi:10.1038/cdd.2011.36; published online 15 April 2011
  NATURE PUBLISHING GROUP, English
  DOI：https://doi.org/10.1038/cdd.2011.36
  DOI ID：10.1038/cdd.2011.36, ISSN：1350-9047, eISSN：1476-5403, ORCID：45646384, Web of Science ID：WOS:000292634000002
• Molecular distinction in genetic regulation of nonphotochemical quenching in rice　　　　　　　　　　　　　　　
  Ichiro Kasajima; Kaworu Ebana; Toshio Yamamoto; Kentaro Takahara; Masahiro Yano; Maki Kawai-Yamada; Hirofumi Uchimiya
  PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, Volume：108, Number：33, First page：13835, Last page：13840, Aug. 2011, [Reviewed]
  Nonphotochemical quenching (NPQ) regulates energy conversion in photosystem II and protects plants from photoinhibition. Here we analyze NPQ capacity in a number of rice cultivars. NPQ was strongly induced under medium and high light intensities in rice leaves. Japonica cultivars generally showed higher NPQ capacities than Indica cultivars when we measured a rice core collection. We mapped NPQ regulator and identified a locus (qNPQ1-2) that seems to be responsible for the difference in NPQ capacity between Indica and Japonica. One of the two rice PsbS homologues (OsPsbS1) was found within the qNPQ1-2 region. PsbS protein was not accumulated in the leaf blade of the mutant harboring transferred DNA insertion in OsPsbS1. NPQ capacity increased as OsPsbS1 expression increased in a series of transgenic lines ectopically expressing OsPsbS1 in an Indica cultivar. Indica cultivars lack a 2.7-kb region at the point 0.4 kb upstream of the OsPsbS1 gene, suggesting evolutionary discrimination of this gene.
  NATL ACAD SCIENCES, English, Scientific journal
  DOI：https://doi.org/10.1073/pnas.1104809108
  DOI ID：10.1073/pnas.1104809108, ISSN：0027-8424, ORCID：45646383, Web of Science ID：WOS:000293895100091
• Bax inhibitor-1: a highly conserved endoplasmic reticulum-resident cell death suppressor　　　　　　　　　　　　　　　
  T. Ishikawa; N. Watanabe; M. Nagano; M. Kawai-Yamada; E. Lam
  CELL DEATH AND DIFFERENTIATION, Volume：18, Number：8, First page：1271, Last page：1278, Aug. 2011, [Reviewed]
  In spite of fundamental differences between plant and animal cells, it is remarkable that some cell death regulators that were identified to control cell death in metazoans can also function in plants. The fact that most of these proteins do not have structural homologs in plant genomes suggests that they may be targeting a highly conserved 'core' mechanism with conserved functions that is present in all eukaryotes. The ubiquitous Bax inhibitor-1 (BI-1) is a common cell death suppressor in eukaryotes that has provided a potential portal to this cell death core. In this review, we will update the current status of our understanding on the function and activities of this intriguing protein. Genetic, molecular and biochemical studies have so far suggested a consistent view that BI-1 is an endoplasmic reticulum (ER)-resident transmembrane protein that can interact with multiple partners to alter intracellular Ca(2+) flux control and lipid dynamics. Functionally, the level of BI-1 protein has been hypothesized to have the role of a rheostat to regulate the threshold of ER-stress inducible cell death. Further, delineation of the cell death suppression mechanism by BI-1 should shed light on an ancient cell death core-control pathway in eukaryotes, as well as novel ways to improve stress tolerance. Cell Death and Differentiation (2011) 18, 1271-1278; doi:10.1038/cdd.2011.59; published online 20 May 2011
  NATURE PUBLISHING GROUP, English
  DOI：https://doi.org/10.1038/cdd.2011.59
  DOI ID：10.1038/cdd.2011.59, ISSN：1350-9047, ORCID：45646380, Web of Science ID：WOS:000292634000006
• Characterization of Glucosylceramides in the Polygonaceae, Rumex obtusifolius L. Injurious Weed　　　　　　　　　　　　　　　
  Masayuki Watanabe; Atsuko Miyagi; Minoru Nagano; Maki Kawai-Yamada; Hiroyuki Imai
  BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY, Volume：75, Number：5, First page：877, Last page：881, May 2011, [Reviewed]
  Rumex obtusifolius L., a member of Polygonaceae, is one of the world's worst weeds. We characterized the glucosylceramide molecular species in leaves of R. obtusifolius by liquid chromatography/tandem mass spectrometry. 4,8-Sphingadienines were principally paired with 2-hydroxy palmitic acids. In contrast, 4-hydroxy-8-sphingenines were chiefly attached to 2-hydroxy fatty acids with 22 to 26 carbon-chain length. A unique characteristic of the 2-hydroxy fatty acid composition of R. obtusifolius was the high content of n-9 monoenoic 2-hydroxy fatty acids with 22 and 24 carbon-chain length. The levels of the Z and E stereoisomers of the 8-unsaturated long-chain bases were reliably distinguished from those in other plant families in ten species of Polygonaceae.
  TAYLOR & FRANCIS LTD, English, Scientific journal
  DOI：https://doi.org/10.1271/bbb.100802
  DOI ID：10.1271/bbb.100802, ISSN：0916-8451, eISSN：1347-6947, ORCID：45646381, Web of Science ID：WOS:000291519100010
• Roles of Plasma Membrane Microdomain in Cell Death Regulation Modulated by Bax Inhibitor-1　　　　　　　　　　　　　　　
  Ishikawa Toshiki; Aki Toshihiko; Yanagisawa Syuichi; Uchimiya Hirofumi; Kawai-Yamada Maki
  Plant and Cell Physiology Supplement, Volume：2011, First page：0404, Last page：0404, 2011
  Bax inhibitor-1 (BI-1) is an endoplasmic reticulum-localized cell death suppressor widely conserved in animals and plants. Our recent studies have revealed that Arabidopsis BI-1 (AtBI-1) interacts with sphingolipid-metabolic enzymes, leading us to further analyses to elucidate roles of BI-1-modulated sphingolipids on cell death regulation. Sphingolipids are well-known to play an important role for formation of liquid-ordered membrane microdomain in plants as well as animals. Here we show compositional alterations of plasma membrane microdomain in AtBI-1 overexpressing rice cells. Glycosphingolipid composition in plasma membrane microdomain was elevated in AtBI-1 overexpressor. Furthermore, shotgun proteomics combined with label-free comparative analysis revealed significant decreases of microdomain-localized proteins possible to participate in cell death regulation, such as hypersensitive cell death-associated proteins and scaffolds for protein complexes in microdomain. Based on these results, we will discuss functional roles of microdomain remodeling in the cell death regulatory mechanism of BI-1.
  The Japanese Society of Plant Physiologists
  DOI：https://doi.org/10.14841/jspp.2011.0.0404.0
  DOI ID：10.14841/jspp.2011.0.0404.0, CiNii Articles ID：130006997013
• Metabolome analysis of oxalate accumulation in Rumex obtusifolius L. using ¹³CO₂ and high CO₂　　　　　　　　　　　　　　　
  Miyagi Atsuko; Kawai-Yamada Maki; Uchimiya Hirofumi
  Plant and Cell Physiology Supplement, Volume：2011, First page：0657, Last page：0657, 2011
  Rumex obtusifolius L. (perennial weed; Polygonaceae) is one of the oxalate-rich plants. Nevertheless, the mechanism of oxalate accumulation in plants is still unclear. Recent metabolome analyses of R. obtusifolius revealed that oxalate contents were highly correlated to citrate and ascorbate (Miyagi et al, Metabolomics, 2010a, b). We reported that oxalate content in leaves was affected by carbon source (such as citrate) in stems. Using CE-MS, we analyzed the carbon effects on oxalate accumulation and other metabolite levels in leaves and stems of R. obtusifolius. The experiment using ¹³CO₂ showed that ¹³C-oxalate was highly accumulated in leaves and that ¹³C mobilization from stems to "new leaves" was observed. High CO₂ (1000 ppm) experiment showed that oxalate content was increased by high CO₂ with Hoagland's solution, although oxalate levels was not changed by CO₂ alone.
  The Japanese Society of Plant Physiologists
  DOI：https://doi.org/10.14841/jspp.2011.0.0657.0
  DOI ID：10.14841/jspp.2011.0.0657.0, CiNii Articles ID：130006995798
• A shotgun proteomics-based approach to identify membrane microdomain proteins involved in regulation of stress-induced cell death　　　　　　　　　　　　　　　
  Ishikawa Toshiki; Aki Toshihiko; Yanagisawa Shuichi; Nagano Minoru; Uchimiya Hirofumi; Kawai-Yamada Maki
  Abstracts for Annual Meeting of Japanese Proteomics Society, Volume：2011, First page：215, Last page：215, 2011
  Japanese Proteomics Society (Japan Human Proteome Organisation), Japanese
  DOI：https://doi.org/10.14889/jhupo.2011.0.215.0
  DOI ID：10.14889/jhupo.2011.0.215.0, CiNii Articles ID：130005454359
• Targeted metabolomics in an intrusive weed, Rumex obtusifolius L., grown under different environmental conditions reveals alterations of organ related metabolite pathway　　　　　　　　　　　　　　　
  Atsuko Miyagi; Kentaro Takahara; Hideyuki Takahashi; Maki Kawai-Yamada; Hirofumi Uchimiya
  METABOLOMICS, Volume：6, Number：4, First page：497, Last page：510, Dec. 2010, [Reviewed]
  This study was intended to analyze the metabolic pathway of Rumex obtusifolius L. (Broad-leaved dock), destructive weeds worldwide, in relation to major environmental factors (light and temperature). It was found that R. obtusifolius can be classified as plants in accumulating major organic acids such as oxalate in leaves and citrate in stems (Miyagi et al., Metabolomics 6:146-155 2010). The organ specific accumulation of certain metabolites was dissected by metabolomics approach in relation to metabolic pathway. Light or dark experiments showed that in the case of the oxalate accumulation, the major or the most dominated pathway was found to be the citrate-isocitrate-oxalate shunt. Furthermore, under the dark and/or low temperature (5A degrees C) leaves showed sustainable growth with normal accumulation of TCA metabolites. Unlike leaves, there was a different pattern of metabolite accumulation in stems. Other metabolites such as amino acids also showed the organ specific alterations under the different ambient environments.
  SPRINGER, English, Scientific journal
  DOI：https://doi.org/10.1007/s11306-010-0220-0
  DOI ID：10.1007/s11306-010-0220-0, ISSN：1573-3882, ORCID：45646391, Web of Science ID：WOS:000283944300004
• Ammonium-dependent respiratory increase is dependent on the cytochrome pathway in Arabidopsis thaliana shoots　　　　　　　　　　　　　　　
  Takushi Hachiya; Chihiro K. Watanabe; Carolina Boom; Danny Tholen; Kentaro Takahara; Maki Kawai-Yamada; Hirofumi Uchimiya; Yukifumi Uesono; Ichiro Terashima; Ko Noguchi
  PLANT CELL AND ENVIRONMENT, Volume：33, Number：11, First page：1888, Last page：1897, Nov. 2010, [Reviewed]
  Oxygen uptake rates are increased when concentrated ammonium instead of nitrate is used as sole N source. Several explanations for this increased respiration have been suggested, but the underlying mechanisms are still unclear. To investigate possible factors responsible for this respiratory increase, we measured the O(2) uptake rate, activity and transcript level of respiratory components, and concentration of adenylates using Arabidopsis thaliana shoots grown in media containing various N sources. The O(2) uptake rate was correlated with concentrations of ammonium and ATP in shoots, but not related to the ammonium assimilation. The capacity of the ATP-coupling cytochrome pathway (CP) and its related genes were up-regulated when concentrated ammonium was sole N source, whereas the ATP-uncoupling alternative oxidase did not influence the extent of the respiratory increase. Our results suggest that the ammonium-dependent increase of the O(2) uptake rate can be explained by the up-regulation of the CP, which may be related to the ATP consumption by the plasma-membrane H+-ATPase.
  WILEY-BLACKWELL PUBLISHING, INC, English, Scientific journal
  DOI：https://doi.org/10.1111/j.1365-3040.2010.02189.x
  DOI ID：10.1111/j.1365-3040.2010.02189.x, ISSN：0140-7791, ORCID：45646385, Web of Science ID：WOS:000283375200009
• Nicotinate/nicotinamide mononucleotide adenyltransferase-mediated regulation of NAD biosynthesis protects guard cells from reactive oxygen species in ABA-mediated stomatal movement in Arabidopsis　　　　　　　　　　　　　　　
  Shin-nosuke Hashida; Taketo Itami; Hideyuki Takahashi; Kentaro Takahara; Minoru Nagano; Maki Kawai-Yamada; Kazuhiro Shoji; Fumiyuki Goto; Toshihiro Yoshihara; Hirofumi Uchimiya
  JOURNAL OF EXPERIMENTAL BOTANY, Volume：61, Number：13, First page：3813, Last page：3825, Aug. 2010, [Reviewed]
  Nicotinamide adenine dinucleotide (NAD) and its derivative nicotinamide adenine dinucleotide phosphate (NADP) are indispensable co-factors in broad-spectrum metabolic events for the maintenance of cellular homeostasis in all living organisms. In this study, the cellular expression levels of NAD biosynthesis genes in Arabidopsis were investigated. A very high expression of nicotinate/nicotinamide mononucleotide adenyltransferase (NMNAT) was observed in the differentiated stomatal guard cells of the leaf surface. Transcriptional analysis confirmed that several genes in the biosynthesis pathway were also highly expressed in stomatal guard cells. In fact, NAD and NADP metabolisms were investigated during stomatal movement. Importantly, the generation of phytohormone ABA-induced reactive oxygen species, which acts as a signal for stomatal closure, was accompanied by markedly decreased levels of NAD. The ABA-induced oxidative stress caused stomatal cell death in the nmnat mutant. Furthermore, stomata partially lost their ability to close leading to drought susceptibility. The stomata were less responsive to opening cues as well. These results indicate that NAD biosynthesis is involved in protecting guard cells from ABA-induced local oxidative stress via the regulation of NMNAT activity. In this study, it is demonstrated that NMNAT is essential for the maintenance of NAD homeostasis enabling sustainable stomatal movement.
  OXFORD UNIV PRESS, English, Scientific journal
  DOI：https://doi.org/10.1093/jxb/erq190
  DOI ID：10.1093/jxb/erq190, ISSN：0022-0957, ORCID：45646389, Web of Science ID：WOS:000280905400028
• Effects of AOX1a Deficiency on Plant Growth, Gene Expression of Respiratory Components and Metabolic Profile Under Low-Nitrogen Stress in Arabidopsis thaliana　　　　　　　　　　　　　　　
  Chihiro K. Watanabe; Takushi Hachiya; Kentaro Takahara; Maki Kawai-Yamada; Hirofumi Uchimiya; Yukifumi Uesono; Ichiro Terashima; Ko Noguchi
  PLANT AND CELL PHYSIOLOGY, Volume：51, Number：5, First page：810, Last page：822, May 2010, [Reviewed]
  Expression of alternative oxidase (AOX) and cyanide (CN)-resistant respiration are often highly enhanced in plants exposed to low-nitrogen (N) stress. Here, we examined the effects of AOX deficiency on plant growth, gene expression of respiratory components and metabolic profiles under low-N stress, using an aox1a knockout transgenic line (aox1a) of Arabidopsis thaliana. We exposed wild-type (WT) and aox1a plants to low-N stress for 7d and analyzed their shoots and roots. In WT plants, the AOX1a mRNA levels and AOX capacity increased in proportion to low-N stress. Expression of the genes of the components for non-phosphorylating pathways and antioxidant enzymes was enhanced, but differences between WT and aox1a plants were small. Metabolome analyses revealed that AOX deficiency altered the levels of certain metabolites, such as sugars and sugar phosphates, in the shoots under low-N stress. However, the carbon (C)/N ratios and carbohydrate levels in aox1a plants were similar to those in the WT under low-N stress. Our results indicated that the N-limited stress induced AOX expression in A. thaliana plants, but the induced AOX may not play essential roles under stress due to low-N alone, and the C/N balance under low-N stress may be tightly regulated by systems other than AOX.
  OXFORD UNIV PRESS, English, Scientific journal
  DOI：https://doi.org/10.1093/pcp/pcq033
  DOI ID：10.1093/pcp/pcq033, ISSN：0032-0781, eISSN：1471-9053, ORCID：45646386, Web of Science ID：WOS:000277734900012
• Metabolome and Photochemical Analysis of Rice Plants Overexpressing Arabidopsis NAD Kinase Gene　　　　　　　　　　　　　　　
  Kentaro Takahara; Ichiro Kasajima; Hideyuki Takahashi; Shin-nosuke Hashida; Taketo Itami; Haruko Onodera; Seiichi Toki; Shuichi Yanagisawa; Maki Kawai-Yamada; Hirofumi Uchimiya
  PLANT PHYSIOLOGY, Volume：152, Number：4, First page：1863, Last page：1873, Apr. 2010, [Reviewed]
  The chloroplastic NAD kinase (NADK2) is reported to stimulate carbon and nitrogen assimilation in Arabidopsis (Arabidopsis thaliana), which is vulnerable to high light. Since rice (Oryza sativa) is a monocotyledonous plant that can adapt to high light, we studied the effects of NADK2 expression in rice by developing transgenic rice plants that constitutively expressed the Arabidopsis chloroplastic NADK gene (NK2 lines). NK2 lines showed enhanced activity of NADK and accumulation of the NADP(H) pool, while intermediates of NAD derivatives were unchanged. Comprehensive analysis of the primary metabolites in leaves using capillary electrophoresis mass spectrometry revealed elevated levels of amino acids and several sugar phosphates including ribose-1,5-bisphosphate, but no significant change in the levels of the other metabolites. Studies of chlorophyll fluorescence and gas change analyses demonstrated greater electron transport and CO2 assimilation rates in NK2 lines, compared to those in the control. Analysis of oxidative stress response indicated enhanced tolerance to oxidative stress in these transformants. The results suggest that NADP content plays a critical role in determining the photosynthetic electron transport rate in rice and that its enhancement leads to stimulation of photosynthesis metabolism and tolerance of oxidative damages.
  AMER SOC PLANT BIOLOGISTS, English, Scientific journal
  DOI：https://doi.org/10.1104/pp.110.153098
  DOI ID：10.1104/pp.110.153098, ISSN：0032-0889, eISSN：1532-2548, ORCID：45646388, Web of Science ID：WOS:000276335900011
• Principal component and hierarchical clustering analysis of metabolites in destructive weeds; polygonaceous plants　　　　　　　　　　　　　　　
  Atsuko Miyagi; Hideyuki Takahashi; Kentaro Takahara; Takayuki Hirabayashi; Yoshiki Nishimura; Takafumi Tezuka; Maki Kawai-Yamada; Hirofumi Uchimiya
  METABOLOMICS, Volume：6, Number：1, First page：146, Last page：155, Mar. 2010, [Reviewed]
  Comprehensive analysis of metabolites using capillary electrophoresis-mass spectrometry was carried out in harmful weeds belonging to Polygonaceae. A principal component analysis revealed clear distinctions among eight Rumex species and Fallopia japonica. Hierarchical clustering data showed that respective metabolites can be grouped due to species differences. There was a positive relationship between oxalate and citrate, oxalate and ascorbate, and oxalate and glutamine. The amount of oxalate per leaf fresh weight was not affected by increased concentrations of exogenously supplied nutrients from Hoagland's formulation in one of the most destructive weeds R. obtusifolius. The oxalate accumulation in this plant is independent of external nutrient level, where nutrient-rich environments apparently stimulate internal constituents such as amino acids and other metabolites.
  SPRINGER, English, Scientific journal
  DOI：https://doi.org/10.1007/s11306-009-0186-y
  DOI ID：10.1007/s11306-009-0186-y, ISSN：1573-3882, ORCID：45646390, Web of Science ID：WOS:000275444800013
• The relationship between cell death suppressor (AtBI-1) and metabolism of sphingolipid fatty acid in Arabidopsis　　　　　　　　　　　　　　　
  Nagano Minoru; Kakuta Chikako; Uchimiya Hirofumi; Kawai-Yamada Maki
  Plant and Cell Physiology Supplement, Volume：2010, First page：0545, Last page：0545, 2010
  Programmed cell death is crucial for developments and responses to various stresses in plants, and is highly regulated by a wide variety of factors. Bax Inhibitor-1 (BI-1) is a widely conserved cell-death suppressor. Arabidopsis BI-1 (AtBI-1) is a 7-times transmembrane protein localized in endoplasmic reticulum (ER), and suppresses cell death induced by oxidative stress, which generates reactive oxygen species (ROS) in plant cells. In addition, calmodulin interacts with the C-terminus of AtBI-1, which is essential for its function. However, the molecular mechanism of BI-1-mediated cell death is still unclear.
  We suggested that AtBI-1 interacts with sphingolipid fatty acid metabolic enzymes via an electron transfer protein, cytochrome b₅. Sphingolipid has a 2-hydroxylated very-long-chain fatty acid (2-hydroxy VLCFA), and it is implied that AtBI-1 interacts with sphingolipid fatty acid 2-hydroxylases (AtFAH) and VLCFA condensing enzymes (AtELO). Here we show the relationship between AtBI-1 and sphingolipid fatty acid generated by AtFAH and AtELO.
  The Japanese Society of Plant Physiologists
  DOI：https://doi.org/10.14841/jspp.2010.0.0545.0
  DOI ID：10.14841/jspp.2010.0.0545.0, CiNii Articles ID：130006991529
• Programmed cell death in plants　　　　　　　　　　　　　　　
  Avijit Das; Maki Kawai-Yamada; Hirofumi Uchimiya
  Abiotic Stress Adaptation in Plants: Physiological, Molecular and Genomic Foundation, First page：371, Last page：383, 2010, [Reviewed]
  Throughout the life cycle of plants, programmed cell death (PCD) is involved in a wide range of deve-lopmental processes and responses against abiotic or biotic stresses. PCD is an active form of cellular suicide controlled by a network of genes. Such phenomenon is associated with recovery of cellular compounds and sustaining plant life. Basic morphological and biochemical features of PCD are believed to be conserved in both plants and animals. Nevertheless, recent studies demonstrate an involvement of organelles such as vacuole and chloroplast in plant cell death regulation, indicating that plants evolved own cell death machinery. Reactive oxygen species (ROS) generated by biotic and abiotic stresses act as a signal that induces plant PCD. This article describes some of the fundamental characteristics of plant PCD and raises points that may lead to a better understanding and novel strategies for plant molecular breeding. © 2010 Springer Science + Business Media B.V. All Rights Reserved.
  Springer Netherlands, English, In book
  DOI：https://doi.org/10.1007/978-90-481-3112-9_17
  DOI ID：10.1007/978-90-481-3112-9_17, SCOPUS ID：84856505544
• Metabolome Analysis of Response to Oxidative Stress in Rice Suspension Cells Overexpressing Cell Death Suppressor Bax Inhibitor-1　　　　　　　　　　　　　　　
  Toshiki Ishikawa; Kentaro Takahara; Takayuki Hirabayashi; Hideo Matsumura; Shizuko Fujisawa; Ryohei Terauchi; Hirofumi Uchimiya; Maki Kawai-Yamada
  PLANT AND CELL PHYSIOLOGY, Volume：51, Number：1, First page：9, Last page：20, Jan. 2010, [Reviewed]
  Bax inhibitor-1 (BI-1) is a cell death suppression factor widely conserved in higher plants and animals. Overexpression of Arabidopsis BI-1 (AtBI-1) in plants confers tolerance to various cell death-inducible stresses. However, apart from the cell death-suppressing activity, little is known about the physiological roles of BI-1-overexpressing plants. In this study, we evaluated the effects of AtBI-1 overexpression on the rice metabolome in response to oxidative stress. AtBI-1-overexpressing rice cells in suspension displayed enhanced tolerance to menadione-induced oxidative stress compared with vector control cells, whereas AtBI-1 overexpression did not influence the increase of intracellular H2O2 concentration or inhibition of oxidative stress-sensitive aconitase activity. Capillary electrophoresismass spectrometry (CE-MS)-based metabolome analysis revealed dynamic metabolic changes in oxidatively stressed rice cells, e.g. depletion of the central metabolic pathway, imbalance of the redox state and energy charge, and accumulation of amino acids. Furthermore, comparative metabolome analysis demonstrated that AtBI-1 overexpression did not affect primary metabolism in rice cells under normal growth conditions but significantly altered metabolite composition within several distinct pathways under cell death-inducible oxidative stress. The AtBI-1-mediated metabolic alteration included recovery of the redox state and energy charge, which are known as important factors for metabolic defense against oxidative stress. These observations suggest that although AtBI-1 does not affect rice metabolism directly, its cell death suppression activity leads to enhanced capacity to acclimate oxidative stress.
  OXFORD UNIV PRESS, English, Scientific journal
  DOI：https://doi.org/10.1093/pcp/pcp162
  DOI ID：10.1093/pcp/pcp162, ISSN：0032-0781, eISSN：1471-9053, ORCID：45646387, Web of Science ID：WOS:000273704500002
• SMAP2 protein potentially medicates the response to synthetic auxin, 2,4-D, in Arabidopsis thaliana　　　　　　　　　　　　　　　
  Akari Nakasone; Maki Kawai-Yamada; Tomohiro Kiyosue; Issay Narumi; Hirofumi Uchimiya; Yutaka Oono
  First page：65, Dec. 2009
• A gene encoding SMALL ACIDIC PROTEIN 2 potentially mediates the response to synthetic auxin, 2,4-dichlorophenoxyacetic acid, in Arabidopsis thaliana.　　　　　　　　　　　　　　　
  Akari Nakasone; Maki Kawai-Yamada; Tomohiro Kiyosue; Issay Narumi; Hirofumi Uchimiya; Yutaka Oono
  Journal of plant physiology, Volume：166, Number：12, First page：1307, Last page：13, Aug. 2009, [Reviewed], ［International magazine］
  The SMALL ACIDIC PROTEIN 2 (SMAP2) gene is a paralogue of the SMAP1 gene that mediates the response to the synthetic auxin 2,4-dichlorophenoxyacetic acid (2,4-D) in the root of Arabidopsis thaliana. Their encoded proteins, SMAP1 and SMAP2, are similar in calculated molecular weight and isoelectric point, and in having a highly conserved phenylalanine and aspartic acid-rich domain. RNA expression analysis showed that SMAP1 mRNA is present throughout the plant body while SMAP2 mRNA is restricted to siliques and anthers. Over-expression of the SMAP2 gene, as well as SMAP1, by 35S cauliflower mosaic virus promoter restored sensitivity to 2,4-D in the 2,4-D-resistant mutant, aar1, which is defective in SMAP1 function. The results suggest that SMAP2 has an ability to mediate the 2,4-D response and is expressed only in restricted tissues.
  English
  DOI：https://doi.org/10.1016/j.jplph.2009.02.005
  DOI ID：10.1016/j.jplph.2009.02.005, ORCID：45646392, PubMed ID：19307045, Web of Science ID：WOS:000268818200008
• Metabolite analysis of alien weed Rumex obtusifolius L.　　　　　　　　　　　　　　　
  Miyagi Atsuko; Hirabayashi Takayuki; Takahashi Hideyuki; Nishimura Yoshiki; Takahara Kentaro; Kawai-Yamada Maki; Uchimiya Hirofumi
  Plant and Cell Physiology Supplement, Volume：2009, First page：0315, Last page：0315, 2009
  Rumex obtusifolius L. (Polygonaceae) is one of the most formidable weeds in infesting fields, arable lands and pastures through the world. In the early 20 century, the occurrence of R. obtusifolius in Japan was first reported in the northern island, whereas today it can be found in almost all areas.
  Rumex plants contain high concentrations of oxalate. Excess uptake of this substance is toxic to animals. In plants, oxalate plays an important role as a source of hydrogen peroxide, which may act as defense molecules. Furthermore, some plants secrete oxalate to the rhizosphere, which could detoxify metallic ions.
  In this investigation, we analyzed the oxalate metabolism in R. obtusifolius. Metabolite analysis by CE-MS showed that higher level of oxalate and amino acids were accumulated in R. obtusifolius. The analysis of R. obtusifolius grown in the dark indicated that citrate in stems play an important role in oxalate accumulation in leaves.
  The Japanese Society of Plant Physiologists
  DOI：https://doi.org/10.14841/jspp.2009.0.0315.0
  DOI ID：10.14841/jspp.2009.0.0315.0, CiNii Articles ID：130006994320
• The Relationship Between NAD Biosynthesis and Stomatal Closure　　　　　　　　　　　　　　　
  Hashida Shin-nosuke; Takahashi Hideyuki; Takahara Kentaro; Nagano Minoru; Kawai-Yamada Maki; Uchimiya Hirofumi
  Plant and Cell Physiology Supplement, Volume：2009, First page：0325, Last page：0325, 2009
  Recent research has underscored the importance of nicotinamide adenine dinucleotide (NAD) biosynthesis. In Arabidopsis, genes involved in the NAD biosynthetic pathway have not been fully determined. Previously, we identified the gene encoding NAD synthetase (NADS), which acts in the final step of NAD biosynthesis. Transcriptional analysis revealed that guard cells (GCs) have relatively high levels of NAD biosynthetic gene expression. The NAD level in the epidermis including GCs was transiently decreased by abscisic acid (ABA), whereas nicotinate mononucleotide adenyltransferase (NMNAT) activity was increase by ABA; however, the increase was significantly delayed compared to the decrease in NAD. The activity of NADS was in a steady state during NAD fluctuation. Stomatal movement and drought tolerance were correlated to the activity of NMNAT. We proposed that NAD biosynthetic activity is involved in regulation of stomatal aperture, possibly via the regulation of NMNAT activity.
  The Japanese Society of Plant Physiologists
  DOI：https://doi.org/10.14841/jspp.2009.0.0325.0
  DOI ID：10.14841/jspp.2009.0.0325.0, CiNii Articles ID：130006994190
• Nicotinamide nucleotides enhance plant metabolic processes　　　　　　　　　　　　　　　
  Takahashi Hideyuki; Takahara Kentaro; Hashida Shin-nosuke; Kawai-Yamada Maki
  Plant and Cell Physiology Supplement, Volume：2009, First page：0174, Last page：0174, 2009
  Nicotinamide nucleotides (NAD and NADP) are important co-factors in various metabolic processes in living organisms. Although both NAD and NADP are redox regulators of living cells, these compounds likely play overlapping but different roles in other biological processes. NAD and NADP are synthesized in NAD biosynthetic pathway comprising NADS, NMNAT, and NADK. The levels of NAD and NADP appear to be regulated by these enzymes. In this study, we analyzed transgenic Arabidopsis plants, which have several levels of NAD and NADP to elucidate the regulating mechanisms of these co-factors. Our results showed that the decrease of NADP level inhibited photosynthetic electron transport. Furthermore, fluctuation of NAD and NADP levels affected several metabolite processes, indicating that NAD and NADP are key factors that control plant metabolism and also suggest the possibility that enhancement of co-factor synthesis is a workable strategy for improving performances of plant.
  The Japanese Society of Plant Physiologists
  DOI：https://doi.org/10.14841/jspp.2009.0.0174.0
  DOI ID：10.14841/jspp.2009.0.0174.0, CiNii Articles ID：130006991067
• The roles of sphingolipid fatty acid hydroxylase in Arabidopsis　　　　　　　　　　　　　　　
  Nagano Minoru; Uchimiya Hirofumi; Kawai-Yamada Maki
  Plant and Cell Physiology Supplement, Volume：2009, First page：0216, Last page：0216, 2009
  Sphingolipids are a large class of lipids ubiquitously present in eukaryotic cell membranes and essential for various cellular reactions such as signal transduction, protein transport and programmed cell death. The structural diversity of sphingolipids derives from more than 300 distinct head groups as well as various modifications on hydrocarbon chains of the hydrophobic ceramide moiety. One of the main modifications of ceramide structure is 2-hydroxylation of the fatty acids. The 2-hydroxylation of the fatty acids is catalyzed by fatty acid hydroxylase (FAH). Two Arabidopsis FAHs (AtFAH1 and AtFAH2) are localized in endoplasmic reticulum (ER) membrane. In addition, AtFAHs were activated by ER-localized cytochrome b5 through their direct interaction. Here we show the functions of AtFAHs and the roles of 2-hydroxy fatty acids in Arabidopsis.
  The Japanese Society of Plant Physiologists
  DOI：https://doi.org/10.14841/jspp.2009.0.0216.0
  DOI ID：10.14841/jspp.2009.0.0216.0, CiNii Articles ID：130006991164
• Chloroplast NAD kinase Enhances Carbon and Nitrogen Metabolism　　　　　　　　　　　　　　　
  Takahashi Hideyuki; Hashida Shin-nosuke; Fujimori Tamaki; Kawai-Yamada Maki; Tamoi Masahiro; Shigeoka Shigeru; Yanagisawa Shuichi; Uchimiya Hirofumi
  Plant and Cell Physiology Supplement, Volume：2008, First page：0297, Last page：0297, 2008
  Chloroplast NAD kinase enhances carbon and nitrogen metabolism
  Chloroplast NAD kinase (NADK2) has been identified as an essential enzyme for chlorophyll synthesis, photosynthetic electron transport, and xanthophyll cycle. Metabolite analysis revealed that the contents of intermediates of the Calvin cycle were increased in transgenic plants overexpressing NADK2 gene (NADK2-OX). The activities of RubisCO and glyceraldehyde-3-phosphate dehydrogenase as well as CO₂ uptake were also increased, indicating that carbon fixation was enhanced in NADK2-OX. On the other hand, the accumulation of free amino acids, especially glutamine and glutamate were observed in NADK2-OX. Furthermore, the expression levels of chloroplast glutamine synthetase and NADH-dependent glutamate synthase genes were increased. The uptake and reduction process of nitrate were also increased. It therefore seemed that the activation of GS/GOGAT pathway and nitrate reduction contributed to amino acid overproduction. These results indicate that NADK2 overexpression enhances both carbon and nitrate metabolism.
  The Japanese Society of Plant Physiologists
  DOI：https://doi.org/10.14841/jspp.2008.0.0297.0
  DOI ID：10.14841/jspp.2008.0.0297.0, CiNii Articles ID：130006994378
• Analysis of AtBI-1-mediated cell death suppression through sphingolipid-related enzymes　　　　　　　　　　　　　　　
  Nagano Minoru; Ihara-Ohori Yuri; Kakuta Chikako; Uchimiya Hirofumi; Kawai-Yamada Maki
  Plant and Cell Physiology Supplement, Volume：2008, First page：0279, Last page：0279, 2008
  In higher plants, programmed cell death is highly regulated by various factors. Bax Inhibitor-1 (BI-1) is a widely conserved cell death suppressor. Arabidopsis BI-1 (AtBI-1) is approximately 26kDa protein with 7 transmembrane domains and localizes in ER. Overexpression of AtBI-1 suppresses H₂O₂-. SA- and elicitor-induced cell death in plant cells. Moreover, AtBI-1 possesses coiled-coil structure in the C-terminus, which is essential in AtBI-1 function and interacts with calmodulin. However, the mechanism of AtBI-1-mediated cell death suppression has not yet been elucidated.
  Recently, we revealed that AtBI-1 interacted with AtFAH (Arabidopsis fatty acid hydroxylase) via cytochrome b₅ (Cb5). Cb5 is an electron transfer protein, which is related to fatty acid synthesis, and AtFAH is a hydroxylase of sphingolipid fatty acid localizing in ER. Lately, the relationships between sphingolipids and cell death have been discussed vigorously. AtBI-1 may suppress cell death through sphingolipid regulation.
  The Japanese Society of Plant Physiologists
  DOI：https://doi.org/10.14841/jspp.2008.0.0279.0
  DOI ID：10.14841/jspp.2008.0.0279.0, CiNii Articles ID：130006993957
• Pollen Dormancy in Nicotinate/nicotinamide Mononucleotide Adenyltransferase Mutant　　　　　　　　　　　　　　　
  Hashida Shin-nosuke; Takahara Kentaro; Takahashi Hideyuki; Kawai-Yamada Maki; Uchimiya Hirofumi
  Plant and Cell Physiology Supplement, Volume：2008, First page：0238, Last page：0238, 2008
  Nicotinamide adenine dinucleotide (NAD) coenzyme is abundant in pollen grain compared to the other inflorescent tissues of Arabidopsis. Pollen lacking a key NAD biosynthetic gene, nicotinate/nicotinamide mononucleotide adenyltransferase (NMNAT), was deficient in tube growth and dormancy. Tracer experiment revealed that the nmnat pollen incompletely eliminated the HPTS-containing moisture, suggesting that nmnat pollen was un-dormant. Under high humidity environment, nmnat/+ plants had long pollen tubes inside the anthers, namely precocious pollen tube growth. Even under dehydrated condition, round pollen with bulges can be distinguished in pollen population of nmnat/+ plants. Un-dormant pollen generally remains to be metabolically active, leading to senescence acceleration. In fact, the longevity of nmnat pollen was quite shorter than that of wild type. Thus, the NAD biosynthesis is essential for acquisition of drought tolerance and transition to pollen dormancy.
  The Japanese Society of Plant Physiologists
  DOI：https://doi.org/10.14841/jspp.2008.0.0238.0
  DOI ID：10.14841/jspp.2008.0.0238.0, CiNii Articles ID：130006993793
• Identification of novel mitochondrial membrane protein (Cdf 3) from Arabidopsis thaliana and its functional analysis in a yeast system　　　　　　　　　　　　　　　
  Kyung-Min Kim; Do-Youn Jun; Sang-Kook Kim; Chang-Kil Kim; Byung Oh Kim; Young-Ho Kim; Wan Park; Jae-Keun Sohn; Aiko Hirata; Maki Kawai-Yamada; Hirofumi Uchimiya; Dai-Hee Kim; Ill-Whan Sul
  JOURNAL OF MICROBIOLOGY AND BIOTECHNOLOGY, Volume：17, Number：6, First page：891, Last page：896, Jun. 2007, []
  We screened the Arabidopsis cDNA library to identify functional suppressors of AtBI-1, a gene that suppresses cell death induced by Bax gene expression in yeast. Cdf 3 encodes a 118-amino-acid protein with a molecular mass of 25 kDa. This protein has two uncharacterized domains at amino acids residues 5-64 and 74-117. In the present study, CDF3 was found to induce growth defects in yeast and arrested yeast growth, although the cell-growth defect was somewhat less than that of Bax. Its localization in the inner mitochondria was essential for suppression of yeast-cell proliferation. The morphological abnormality of the intracellular network, which is a hallmark of AtBI-1, was attenuated by Cdf 3 expression.
  KOREAN SOC MICROBIOLOGY & BIOTECHNOLOGY
  ISSN：1017-7825, eISSN：1738-8872, Web of Science ID：WOS:000247703500002
• Young Investigator Award - Plant cell death as an oxidative stress response　　　　　　　　　　　　　　　
  Maki Kawai-Yamada
  PLANT AND CELL PHYSIOLOGY, Volume：48, First page：S16, Last page：S16, 2007, []
  OXFORD UNIV PRESS
  DOI：https://doi.org/10.14841/jspp.2007.0.A002.0
  DOI ID：10.14841/jspp.2007.0.A002.0, ISSN：0032-0781, ORCID：45646410, Web of Science ID：WOS:000245922700060
• Mechanism of metabolic activation through altered NAD metabolism
  Maki Kawai-Yamada; Hideyuki Takahashi; Shin-Nosuke Hashida; Hirofumi Uchimiya
  PLANT AND CELL PHYSIOLOGY, Volume：48, First page：S9, Last page：S9, 2007, []
  OXFORD UNIV PRESS
  ISSN：0032-0781, ORCID：45646407, Web of Science ID：WOS:000245922700036
• Functional analysis of Arabidopsis thaliana NAD biosynthetic genes　　　　　　　　　　　　　　　
  Shin-nosuke Hashida; Taketo Itami; Hideyuki Takahashi; Maki Kawai-Yamada; Hirofumi Uchimiya
  PLANT AND CELL PHYSIOLOGY, Volume：48, First page：S42, Last page：S42, 2007, []
  OXFORD UNIV PRESS
  DOI：https://doi.org/10.14841/jspp.2007.0.104.0
  DOI ID：10.14841/jspp.2007.0.104.0, ISSN：0032-0781, ORCID：45646406, Web of Science ID：WOS:000245922700166
• The mitochondrial fission regulator DRP3B does not regulate cell death in plants　　　　　　　　　　　　　　　
  Keiko Yoshinaga; Masaru Fujimoto; Shin-Ichi Arimura; Nobuhiro Tsutsumi; Hirofumi Uchimiya; Maki Kawai-Yamada
  Handbook of Environmental Chemistry, Volume 5: Water Pollution, Volume：97, Number：6, First page：1145, Last page：1149, Jun. 2006, []
  Background and Aims: Recent reports have described dramatic alterations in mitochondrial morphology during metazoan apoptosis. A dynamin-related protein (DRP) associated with mitochondrial outer membrane fission is known to be involved in the regulation of apoptosis. This study analysed the relationship between mitochondrial fission and regulation of plant cell death. Methods: Transgenic plants were generated possessing Arabidopsis DRP3B (K56A), the dominant-negative form of Arabidopsis DRP, mitochondrial-targeted green fluorescent protein and mouse Bax. Key Results: Arabidopsis plants over-expressing DRP3B (K56A) exhibited long tubular mitochondria. In these plants, mitochondria appeared as a string-of-beads during cell death. This indicates that DRP3B (K56A) prevented mitochondrial fission during plant cell death. However, in contrast to results for mammalian cells and yeast, Bax-induced cell death was not inhibited in DRP3B (K56A)-expressing plant cells. Similarly, hydrogen peroxide-, menadione-, darkness- and salicylic acid-induced cell death was not inhibited by DRP3B (K56A) expression. Conclusions: These results indicate that the systems controlling cell death in animals and plants are not common in terms of mitochondrial fission. © The Author 2006. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved.
  DOI：https://doi.org/10.1093/aob/mcl057
  DOI ID：10.1093/aob/mcl057, ISSN：1433-6863, SCOPUS ID：33947317551
• Analysis of the Arabidopsis thaliana cell growth defect factor 2 (Cdf2) suppressing yeast cell proliferation　　　　　　　　　　　　　　　
  Kyung-Min Kim; Yong Suk Lim; Ill Whan Sul; Aiko Hirata; Maki Kawai-Yamada; Hirofumi Uchimiya
  KOREAN JOURNAL OF GENETICS, Volume：28, Number：2, First page：201, Last page：206, Jun. 2006, []
  The Cdf2 gene, which is a gene reported to suppress the cell death induced by Bax gene expression in yeast, was screened from an Arabidopsis cDNA library using the yeast screening system harboring GAL1 fused to AtBI-1. Cdf2 encodes a protein consisting of 118 amino acid residues with a molecular weight of 28.8 kDa. The protein has one transmembrane domain in the middle of the amino acid sequence (29-106). Cdf2 induces a growth defect in yeast. The Cdf2-GFP fusion protein was localized in the vacuole of Cdf2 expression attenuated the morphological abnormality of the intracellular network, which is a hallmark of AtBI-1.
  GENETICS SOC KOREA
  ISSN：0254-5934, Web of Science ID：WOS:000239182700014
• NMNAT, a key enzyme in NAD biosynthesis, required for normal pollen tube elongation in Arabidopsis　　　　　　　　　　　　　　　
  SN Hashida; H Takahashi; M Kawai-Yamada; H Uchimiya
  PLANT AND CELL PHYSIOLOGY, Volume：47, First page：S148, Last page：S148, 2006, []
  OXFORD UNIV PRESS
  DOI：https://doi.org/10.14841/jspp.2006.0.495.0
  DOI ID：10.14841/jspp.2006.0.495.0, ISSN：0032-0781, ORCID：45646417, Web of Science ID：WOS:000236401401077
• Metabolome analysis of rice cells treated with the cell wall extracts of Magnaporthe grisea
  H Takahashi; H Matsumura; M Kawai-Yamada; H Uchimiya
  PLANT AND CELL PHYSIOLOGY, Volume：47, First page：S83, Last page：S83, 2006, []
  OXFORD UNIV PRESS
  ISSN：0032-0781, ORCID：45646416, Web of Science ID：WOS:000236401400329
• Metabolic studies of oxalate rich plants
  A Miyagi; H Takahashi; M Kawai-Yamada; H Uchimiya
  PLANT AND CELL PHYSIOLOGY, Volume：47, First page：S60, Last page：S60, 2006, []
  OXFORD UNIV PRESS
  ISSN：0032-0781, ORCID：45646415, Web of Science ID：WOS:000236401400240
• Analysis of proteins interacting with cell death suppressor (AtBI-1)
  M Nagano; Y Ihara-Ohori; K Yoshinaga; H Uchimiya; M Kawai-Yamada
  PLANT AND CELL PHYSIOLOGY, Volume：47, First page：S43, Last page：S43, 2006, []
  OXFORD UNIV PRESS
  ISSN：0032-0781, ORCID：45646412, Web of Science ID：WOS:000236401400171
• The rice metallothionein gene promoter does not direct foreign gene expression in seed endosperm　　　　　　　　　　　　　　　
  H Fukuzawa; LH Yu; C Umeda-Hara; M Tagawa; H Uchimiya
  PLANT CELL REPORTS, Volume：23, Number：4, First page：231, Last page：235, Oct. 2004, []
  We generated transgenic tobacco and rice plants harboring a chimeric gene consisting of the 5'-upstream sequence of the rice metallothionein gene (ricMT) fused to the beta-glucuronidase (GUS) gene. The activity and tissue-specific expression of the ricMT promoter were demonstrated in these transgenic plants. In the transgenic rice plants, despite substantial levels of GUS activity in the shoot and root, almost no GUS signal was detected in the endosperm. Thus, the ricMT promoter could be useful in avoiding accumulation of undesired proteins in the seed endosperm.
  SPRINGER
  DOI：https://doi.org/10.1007/s00299-004-0813-z
  DOI ID：10.1007/s00299-004-0813-z, ISSN：0721-7714, Web of Science ID：WOS:000224614500008
• Isolation of a cotton CAP gene: a homologue of adenylyl cyclase-associated protein highly expressed during fiber elongation
  M Kawai; S Aotsuka; H Uchimiya
  PLANT AND CELL PHYSIOLOGY, Volume：39, Number：12, First page：1380, Last page：1383, Dec. 1998, []
  The cDNA encoding CAP (adenylyl cyclase-associated protein) was isolated from a cotton (Gossypium hirsutum) fiber cDNA library. The cDNA (GhCAP) contained an open reading frame that encoded 471 amino acid residues. RNA blot analysis showed that the cotton CAP gene was expressed mainly in young fibers.
  JAPANESE SOC PLANT PHYSIOLOGISTS
  ISSN：0032-0781, ORCID：45646432, Web of Science ID：WOS:000077761600019
• Dissection of cell cycle and cell death in rice root.
  内宮博文; 川合真紀; 梅田(原)千景; 梅田正明
  育種学雑誌, Volume：48, First page：32, Apr. 1998
  ISSN：0536-3683, J-Global ID：200902180414092543
• Mechanism of aerenchyma formation by cell death.
  川合真紀; 梅田正明; 内宮博文
  月刊組織培養, Volume：22, Number：1, First page：8, Last page：12, Jan. 1996
  ISSN：0386-1791, J-Global ID：200902141757145191
• TISSUE-SPECIFIC LOCALIZATION OF ADENYLATE KINASE IN RICE (ORYZA-SATIVA L) PLANTS
  M KAWAI; H UCHIMIYA
  JOURNAL OF PLANT PHYSIOLOGY, Volume：146, Number：3, First page：239, Last page：242, Jun. 1995, []
  Anti-adenylate kinase (AK) antibody was used to locate AK protein in organs and tissues of rice plants. This antibody reacted with a 27-kDa protein in callus, root, and leaf tissues. Tissue-printing immunoblot analysis revealed that AK proteins were expressed intensively in vascular tissues.
  GUSTAV FISCHER VERLAG
  ISSN：0176-1617, ORCID：45646436, Web of Science ID：WOS:A1995RJ37600008
• Strcuture and stress response of rice adenylate kinase(AK) genes.
  川合真紀; 梅田正明; 内宮博文
  育種学雑誌, Volume：44, First page：253, 1994
  ISSN：0536-3683, J-Global ID：200902144795110961
• Structure and expression of rice nucleotide kinase (AK and NDK) genes.
  川合真紀; 矢野明; 梅田正明; 内宮博文
  Jpn J Breed, Volume：43, First page：39, 1993
  ISSN：0536-3683, J-Global ID：200902124807785403
• MOLECULAR CHARACTERIZATION OF CDNA-ENCODING FOR ADENYLATE KINASE OF RICE (ORYZA-SATIVA L)　　　　　　　　　　　　　　　
  M KAWAI; S KIDOU; A KATO; H UCHIMIYA
  PLANT JOURNAL, Volume：2, Number：6, First page：845, Last page：854, Nov. 1992, []
  Two types of genes (Adk-a, and Adk-b) encoding for adenylate kinase (AK, EC 2.7.4.3.) were isolated from the cDNA library constructed from poly(A)+ RNA of rice (Oryza sativa L.). Two cDNAs were heterogeneous at 5' and 3' ends of non-coding sequences and had possible polyadenylation signals. One of the genes, Adk-a, had 1154 bp sequences encoding 241 amino acid residues, while the other type, Adk-b, contained 1085 bp sequences encoding for 243 amino acid residues. Homology between Adk-a and Adk-b was 73.7% in nucleotide sequences, and 90.8% in amino acid level. Two genes showed about 53% homology to bovine mitochondrial adenylate kinase (AK2) at nucleotide and amino acid levels. Concerning the codon usage of rice AK genes, T was abundant at the third position of a codon in the reading frames.
  In order to examine the enzyme activity of the protein encoded by the rice cDNA, Adk-a was cloned into an expression vector, pUC119, which was introduced into Escherichia coli strain CV2, a temperature-sensitive mutant of adenylate kinase. We found that the transformant carrying the rice Adk-a gene in the sense orientation recovered cell growth at non-permissive high temperature (42-degrees-C) and expressed enzyme activities higher than the untransformed CV2 and the transformant possessing Adk-a cDNA in the antisense orientation. These observations suggest that rice Adk-a codes a biologically active enzyme. Furthermore, sucrose was found to regulate the transcription of AK genes in rice cell cultures. Organ related accumulation of mRNA in whole plants was also found.
  BLACKWELL SCIENCE LTD
  DOI：https://doi.org/10.1046/j.1365-313X.1992.t01-1-00999.x
  DOI ID：10.1046/j.1365-313X.1992.t01-1-00999.x, ISSN：0960-7412, ORCID：45646437, Web of Science ID：WOS:A1992JY25100002

• Analyses of transcriptional regulation of cuticular wax accumulation in response to dehydration　　　　　　　　　　　　　　　
  浦野薫; 圓山恭之進; 大島良美; 大島良美; 坂本真吾; 石川寿樹; 川合真紀; 佐藤繭子; 豊岡公徳; 篠崎和子; 篠崎和子; 篠崎一雄
  日本植物生理学会年会(Web), Volume：62nd, 2021
  J-Global ID：202102212550428101
• イネ品種間におけるシュウ酸蓄積の比較解析　　　　　　　　　　　　　　　
  宮城敦子; 安達俊輔; 大川泰一郎; 川合真紀
  日本植物細胞分子生物学会大会・シンポジウム講演要旨集, Volume：37th, First page：68, 25 Aug. 2019
  Japanese
  J-Global ID：201902223570072576
• 光合成誘導反応のイネ品種間差に関わる生理的要因の解析　　　　　　　　　　　　　　　
  安達俊輔; 田中佑; 宮城敦子; 鹿島誠; 手塚あゆみ; 戸谷吉博; 小林俊造; 大久保智司; 清水浩; 川合真紀; 永野惇; 矢守航
  日本作物学会講演会要旨集, Volume：247th, First page：65, 28 Mar. 2019
  Japanese
  J-Global ID：201902277546415649
• 光合成における電子受容体NADP⁺供給システムと電子伝達の交互作用　　　　　　　　　　　　　　　
  橋田慎之介; 川合真紀
  Volume：60th, 2019
  J-Global ID：201902254199254282
• シロイヌナズナVND遺伝子群の遺伝学的解析
  伊藤敦也; 久保稔; 大谷美沙都; 石川寿樹; 川合真紀; 出村拓; 山口雅利
  日本植物細胞分子生物学会大会・シンポジウム講演要旨集, Volume：36th, First page：153, 15 Aug. 2018
  Japanese
  J-Global ID：201802264094945466
• イネにおける染色体部分置換がシュウ酸蓄積に及ぼす影響
  宮城敦子; 安達俊輔; 野口航; 常田岳志; 臼井靖浩; 中村浩史; 酒井英光; 長谷川利拡; 山本敏夫; 大川泰一郎; 川合真紀
  日本植物細胞分子生物学会大会・シンポジウム講演要旨集, Volume：36th, First page：115, 15 Aug. 2018
  Japanese
  J-Global ID：201802258186947949
• イオンビーム照射イネ系統におけるメタボローム解析
  宮城敦子; 西丸拓也; 大野豊; 長谷純宏; 川合真紀
  日本植物細胞分子生物学会大会・シンポジウム講演要旨集, Volume：34th, First page：77, 20 Aug. 2016
  Japanese
  J-Global ID：201602249993963032
• イオンビームを照射した高シュウ酸植物エゾノギシギシの代謝解析
  宮城敦子; 北野沙也佳; 長谷純宏; 大野豊; 山口雅利; 川合真紀
  日本植物学会大会研究発表記録, Volume：79th, First page：134, 01 Sep. 2015
  Japanese
  J-Global ID：201502214850620962
• NAD(P)代謝改変シロイヌナズナの作出および代謝解析　　　　　　　　　　　　　　　
  鈴木渉太; 宮城敦子; 石川寿樹; 刑部敬史; 長野稔; 山口雅利; 川合真紀
  日本植物細胞分子生物学会大会・シンポジウム講演要旨集, Volume：33rd, First page：140, 20 Jul. 2015
  Japanese
  J-Global ID：201502202919376033
• Metabolome analysis of leaves of Rumex obtusifolius L. irradiated with ion beams.　　　　　　　　　　　　　　　
  Atsuko Miyagi; Sayaka Kitano; Yutaka Oono; Yoshihiro Hase; Maki Kawai-Yamada
  JAEA Review 2014-050, First page：114, Mar. 2015
  Japanese
• 放射線照射高シュウ酸植物のメタボローム解析
  宮城敦子; 北野沙也佳; 大野豊; 長谷純宏; 川合真紀
  日本植物細胞分子生物学会大会・シンポジウム講演要旨集, Volume：32nd, First page：100, 30 Jul. 2014
  Japanese
  J-Global ID：201402237207551572
• Effects of gamma-ray irradiation on oxalate Metabolism in Rumex obtusifolius L.　　　　　　　　　　　　　　　
  Sayaka Kitano; Atsuko Miyagi; Yutaka Ohno; Yoshihiro Hase; Issay Narumi; Hirofumi Uchimiya; Maki Kawai-Yamada
  JAEA-Review, Volume：2013-059, First page：108, Mar. 2014
• 植物のアルミニウムストレスと代謝物解析
  Atsuko Miyagi; Maki Kawai-Yamada; Hirofumi Uchimiya
  農業および園芸, Volume：89, Number：1, First page：34, Last page：39, 01 Jan. 2014
  Japanese, Introduction commerce magazine
  ISSN：0369-5247, J-Global ID：201402268976322988
• ガンマ線が高シュウ酸植物の代謝に及ぼす影響
  北野沙也佳; 宮城敦子; 大野豊; 長谷純弘; 鳴海一成; 山口雅利; 内宮博文; 川合真紀
  日本植物学会大会研究発表記録, Volume：77th, First page：185, 20 Aug. 2013
  Japanese
  J-Global ID：201302255221317192
• 雑草のメタボローム研究〔3〕—エゾノギシギシの二酸化炭素応答—　　　　　　　　　　　　　　　
  宮城敦子; 川合真紀; 内宮博文
  農業および園芸, Volume：87, Number：7, First page：694-700, Jul. 2012
  Japanese
  ISSN：0369-5247, J-Global ID：201202276171386520
• Theories in PAM chlorophyll fluorescence measurement of plant leaves　　　　　　　　　　　　　　　
  Ichiro Kasajima; Maki Kawai-Yamada; Maki Kawai-Yamada; Hirofumi Uchimiya; Hirofumi Uchimiya
  Photochemistry: UV/VIS Spectroscopy, Photochemical Reactions and Photosynthesis, First page：351, Last page：371, 01 Dec. 2011
  Chlorophyll in chloroplasts is the light-harvesting pigment of plant leaves. Chlorophyll is excited by light energy to reach excitation state. This excitation energy is de-excited by several processes in planta. Of the two photochemical apparatus of photosynthetic electron transport (photosystem I and photosystem II), rate constants of photochemical reactions around photosystem II can be measured with chlorophyll fluorescence, because it is mainly emitted from photosystem II. Fluorescence itself is one of the de-excitation processes. Internal conversion and intersystem crossing also dissipates excitation energy. These three processes are called as 'basal dissipation'. In addition to basal dissipation, excitation energy is consumed to drive 'photochemistry' (photosynthetic electron transport). Under illumination, a mechanism called as 'non-photochemical quenching' is induced by biochemical mechanisms and dissipates excessive energy as heat. Based on the Stern-Volmer relationship between fluorescence intensity and de-excitation rate constants, relative sizes of rate constants for these de-excitation pathways (basal dissipation, photochemistry and non-photochemical quenching) can be calculated by the technique called as Pulse Amplitude Modulation (PAM). In the PAM analysis of chlorophyll fluorescence, yield of fluorescence is measured with weak pulses of illumination. PAM technique enables measurement of fluorescence yield under both dark and illuminated conditions. Illumination of the leaf results in decrease of photochemistry and increase of non-photochemical quenching. Such changes are measured by several fluorescence parameters. The principle equation to calculate relative sizes of rate constants from chlorophyll fluorescence intensities was presented by Kitajima and Butler. Since Kitajima and Butler, PAM was introduced and non-photochemical quenching was discovered, thus the principle equation was updated. This updated principle equation will be referred to as 'Kitajima-Butler equation' in this review. Many fluorescence parameters have been proposed from calculation of Kitajima-Butler equation. These parameters were first represented by complex formulas, and recent finding even showed that relative sizes of rate constants of all de-excitation pathways are easily described as the comparison between inverse values of fluorescence intensities. PAM fluorescence analysis provides high-throughput method to estimate photosynthetic rate, damage by stressful conditions (photoinhibition) and size of non-photochemical quenching in living plant leaves. PAM fluorescence measurement is routinely used to estimate and visualize the effects of plant genes or stress treatments on these processes. © 2011 by Nova Science Publishers, Inc. All rights reserved.
  SCOPUS ID：84892840962
• 雑草のメタボローム研究〔2〕—環境ストレス耐性とバイオマスエネルギー素材—　　　　　　　　　　　　　　　
  宮城敦子; 川合真紀; 内宮博文
  農業および園芸, Volume：86, Number：11, First page：1153-1159, Nov. 2011
  Japanese
  ISSN：0369-5247, J-Global ID：201102253283160276
• 雑草のメタボローム研究〔1〕—タデ科植物種間比較解析—　　　　　　　　　　　　　　　
  宮城敦子; 川合真紀; 内宮博文
  農業および園芸, Volume：86, Number：10, First page：1062-1066, Oct. 2011
  Japanese
  ISSN：0369-5247, J-Global ID：201102266438000976
• Promotion of Ageing in Transgenic Arabidopsis Plants Overexpressing Nicotinamide Adenine Dinucleotide Synthetase　　　　　　　　　　　　　　　
  Hashida Shin-nosuke; Takahara Kentaro; Johkan Masafumi; Shoji Kazuhiro; Goto Fumiyuki; Yoshihara Toshihiro; Kawai-Yamada Maki; Uchimiya Hirofumi
  Plant and Cell Physiology Supplement, Volume：52nd, First page：742, Last page：742, 2011
  Modulation of cellular energy homeostasis is an attractive alternative to improve crop yield and plant performance under stressful conditions. Previously, we reported that overexpression of Arabidopsis NAD kinase2, which produces chloroplastic NADP, promoted nitrogen assimilation in Arabidopsis. Consequently, metabolites associated with the Calvin cycle were also accumulated. In this study, we generated transgenic plants overexpressing Arabidopsis NAD synthetase gene (NADS). NADS overexpressor plants did not show any remarkable changes in vegetative growth and the level of NAD(P)(H) was unexpectedly unchanged albeit enhanced NADS activity. However, NADS overexpression caused early ageing coincidentally with bolting. Then, the levels of NAD⁺ was drastically decreased and the levels of intermediates of NAD biosynthesis (NaMN and NaAD) and NAD derivatives (nicotinate and nicotinamide) were dramatically increased in NADS overexpressors after bolting. These results suggest that the levels of NAD(P)(H) could be kept properly during vegetative phase even under NADS overexpression and that bolting may act as a signal for the alteration of NAD homeostasis.
  The Japanese Society of Plant Physiologists
  DOI：https://doi.org/10.14841/jspp.2011.0.0742.0
  DOI ID：10.14841/jspp.2011.0.0742.0, J-Global ID：201102296779639831, CiNii Articles ID：130006998144
• Loss of Calmodulin Binding to Bax Inhibitor-1 Affects Pseudomonas-mediated Hypersensitive Response-associated Cell Death in Arabidopsis thaliana　　　　　　　　　　　　　　　
  Maki Kawai-Yamada; Zenta Hori; Taro Ogawa; Yuri Ihara-Ohori; Katsunori Tamura; Minoru Nagano; Toshiki Ishikawa; Hirofumi Uchimiya
  JOURNAL OF BIOLOGICAL CHEMISTRY, Volume：284, Number：41, First page：27998, Last page：28003, Oct. 2009
  Bax inhibitor-1 (BI-1) is a cell death suppressor protein conserved across a variety of organisms. The Arabidopsis atbi1-1 plant is a mutant in which the C-terminal 6 amino acids of the expressed BI-1 protein have been replaced by T-DNA insertion. This mutant BI-1 protein (AtBI-CM) produced in Escherichia coli can no longer bind to calmodulin. A promoter-reporter assay demonstrated compartmentalized expression of BI-1 during hypersensitive response, introduced by the inoculation of Pseudomonas syringae possessing the avrRTP2 gene, Pst(avr-RPT2). In addition, both BI-1 knockdown plants and atbi1-1 showed increased sensitivity to Pst(avrRPT2)-induced cell death. The results indicated that the loss of calmodulin binding reduces the cell death suppressor activity of BI-1 in planta.
  AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC, English
  DOI：https://doi.org/10.1074/jbc.M109.037234
  DOI ID：10.1074/jbc.M109.037234, ISSN：0021-9258, CiNii Articles ID：80020605891, PubMed ID：19674971, Web of Science ID：WOS:000270676300028
• Estimation of the Relative Sizes of Rate Constants for Chlorophyll De-excitation Processes Through Comparison of Inverse Fluorescence Intensities　　　　　　　　　　　　　　　
  Ichiro Kasajima; Kentaro Takahara; Maki Kawai-Yamada; Hirofumi Uchimiya
  PLANT AND CELL PHYSIOLOGY, Volume：50, Number：9, First page：1600, Last page：1616, Sep. 2009
  The paper derives a simple way to calculate the linear relationships between all separable groups of rate constants for de-excitation of Chl a excitation energy. This is done by comparison of the inverse values of chlorophyll fluorescence intensities and is based on the matrix model of Kitajima and Butter and on the take model of energy exchange among PSII centers. Compared with the outputs of earlier, similar calculations, the results presented here add some linear comparisons of the relative sizes of rate constants without the need for F(0)' measurement. This enables us to regenerate the same alternative formula to calculate q(L), as presented previously, in a different and simple form. The same former equation to calculate F(0)' value from F(m), F(m)' and F(0) values is also regenerated in our calculation system in a simple form. We also apply relaxation analysis to separate the rate constant for non-photochemical quenching (k(NPQ)) into the rate constant for a fast-relaxing non-photochemical quenching (k(fast)) and the rate constant for slow-relaxing non-photochemical quenching (k(slow)). Changes in the sizes of rate constants were measured in Arabidopsis thaliana and in rice.
  OXFORD UNIV PRESS, English
  DOI：https://doi.org/10.1093/pcp/pcp102
  DOI ID：10.1093/pcp/pcp102, ISSN：0032-0781, CiNii Articles ID：10027343022, PubMed ID：19602498, Web of Science ID：WOS:000270547300003
• Pleiotropic Modulation of Carbon and Nitrogen Metabolism in Arabidopsis Plants Overexpressing the NAD kinase2 Gene　　　　　　　　　　　　　　　
  Hideyuki Takahashi; Kentaro Takahara; Shin-nosuke Hashida; Takayuki Hirabayashi; Tamaki Fujimori; Maki Kawai-Yamada; Tomoyuki Yamaya; Shuichi Yanagisawa; Hirofumi Uchimiya
  PLANT PHYSIOLOGY, Volume：151, Number：1, First page：100, Last page：113, Sep. 2009
  Nicotinamide nucleotides (NAD and NADP) are important cofactors in many metabolic processes in living organisms. In this study, we analyzed transgenic Arabidopsis (Arabidopsis thaliana) plants that overexpress NAD kinase2 (NADK2), an enzyme that catalyzes the synthesis of NADP from NAD in chloroplasts, to investigate the impacts of altering NADP level on plant metabolism. Metabolite profiling revealed that NADP(H) concentrations were proportional to NADK activity in NADK2 overexpressors and in the nadk2 mutant. Several metabolites associated with the Calvin cycle were also higher in the overexpressors, accompanied by an increase in overall Rubisco activity. Furthermore, enhanced NADP(H) production due to NADK2 overexpression increased nitrogen assimilation. Glutamine and glutamate concentrations, as well as some other amino acids, were higher in the overexpressors. These results indicate that overexpression of NADK2 either directly or indirectly stimulates carbon and nitrogen assimilation in Arabidopsis under restricted conditions. Importantly, since neither up-regulation nor down-regulation of NADK2 activity affected the sum amount of NAD and NADP or the redox state, the absolute level of NADP and/or the NADP/NAD ratio likely plays a key role in regulating plant metabolism.
  AMER SOC PLANT BIOLOGISTS, English
  DOI：https://doi.org/10.1104/pp.109.140665
  DOI ID：10.1104/pp.109.140665, ISSN：0032-0889, CiNii Articles ID：80020615084, PubMed ID：19587098, Web of Science ID：WOS:000269522200009
• A gene encoding SMALL ACIDIC PROTEIN 2 potentially mediates the response to synthetic auxin, 2,4-dichlorophenoxyacetic acid, in Arabidopsis thaliana.　　　　　　　　　　　　　　　
  Akari Nakasone; Maki Kawai-Yamada; Tomohiro Kiyosue; Issay Narumi; Hirofumi Uchimiya; Yutaka Oono
  Journal of plant physiology, Volume：166, Number：12, First page：1307, Last page：13, 15 Aug. 2009, [International magazine]
  The SMALL ACIDIC PROTEIN 2 (SMAP2) gene is a paralogue of the SMAP1 gene that mediates the response to the synthetic auxin 2,4-dichlorophenoxyacetic acid (2,4-D) in the root of Arabidopsis thaliana. Their encoded proteins, SMAP1 and SMAP2, are similar in calculated molecular weight and isoelectric point, and in having a highly conserved phenylalanine and aspartic acid-rich domain. RNA expression analysis showed that SMAP1 mRNA is present throughout the plant body while SMAP2 mRNA is restricted to siliques and anthers. Over-expression of the SMAP2 gene, as well as SMAP1, by 35S cauliflower mosaic virus promoter restored sensitivity to 2,4-D in the 2,4-D-resistant mutant, aar1, which is defective in SMAP1 function. The results suggest that SMAP2 has an ability to mediate the 2,4-D response and is expressed only in restricted tissues.
  English
  DOI：https://doi.org/10.1016/j.jplph.2009.02.005
  DOI ID：10.1016/j.jplph.2009.02.005, PubMed ID：19307045
• Functional association of cell death suppressor, Arabidopsis Bax inhibitor-1, with fatty acid 2-hydroxylation through cytochrome b(5)　　　　　　　　　　　　　　　
  Minoru Nagano; Yuri Ihara-Ohori; Hiroyuki Imai; Noriko Inada; Masaru Fujimoto; Nobuhiro Tsutsumi; Hirofumi Uchimiya; Maki Kawai-Yamada
  PLANT JOURNAL, Volume：58, Number：1, First page：122, Last page：134, Apr. 2009
  Bax inhibitor-1 (BI-1) is a widely conserved cytoprotective protein localized in the endoplasmic reticulum (ER) membrane. We identified Arabidopsis cytochrome b(5) (AtCb5) as an interactor of Arabidopsis BI-1 (AtBI-1) by screening the Arabidopsis cDNA library with the split-ubiquitin yeast two-hybrid (suY2H) system. Cb5 is an electron transfer protein localized mainly in the ER membrane. In addition, a bimolecular fluorescence complementation (BiFC) assay and fluorescence resonance energy transfer (FRET) analysis confirmed that AtBI-1 interacted with AtCb5 in plants. On the other hand, we found that the AtBI-1-mediated suppression of cell death in yeast requires Saccharomyces cerevisiae fatty acid hydroxylase 1 (ScFAH1), which had a Cb5-like domain at the N terminus and interacted with AtBI-1. ScFAH1 is a sphingolipid fatty acid 2-hydroxylase localized in the ER membrane. In contrast, AtFAH1 and AtFAH2, which are functional ScFAH1 homologues in Arabidopsis, had no Cb5-like domain, and instead interacted with AtCb5 in plants. These results suggest that AtBI-1 interacts with AtFAHs via AtCb5 in plant cells. Furthermore, the overexpression of AtBI-1 increased the level of 2-hydroxy fatty acids in Arabidopsis, indicating that AtBI-1 is involved in fatty acid 2-hydroxylation.
  WILEY-BLACKWELL, English
  DOI：https://doi.org/10.1111/j.1365-313X.2008.03765.x
  DOI ID：10.1111/j.1365-313X.2008.03765.x, ISSN：0960-7412, eISSN：1365-313X, Web of Science ID：WOS:000264612800010
• 2,4‐D応答に関わるタンパク質,Small Acidic Protein 1(SMAP1)はCOP9シグナロソーム(CSN)と結合する
  中曽根光; 川合真紀; 鳴海一成; 内宮博文; 大野豊
  日本植物生理学会年会要旨集, Volume：50th, First page：250, 16 Mar. 2009
  Japanese
  J-Global ID：200902220454582383
• CO2 regulator SLAC1 and its homologues are essential for anion homeostasis in plant cells　　　　　　　　　　　　　　　
  Juntaro Negi; Osamu Matsuda; Takashi Nagasawa; Yasuhiro Oba; Hideyuki Takahashi; Maki Kawai-Yamada; Hirofumi Uchimiya; Mimi Hashimoto; Koh Iba
  NATURE, Volume：452, Number：7186, First page：483, Last page：U13, Mar. 2008
  The continuing rise in atmospheric [ CO2] is predicted to have diverse and dramatic effects on the productivity of agriculture, plant ecosystems and gas exchange(1-3). Stomatal pores in the epidermis provide gates for the exchange of CO2 and water between plants and the atmosphere, processes vital to plant life(4-6). Increased [ CO2] has been shown to enhance anion channel activity(7) proposed to mediate efflux of osmoregulatory anions ( Cl- and malate(2-)) from guard cells during stomatal closure(8,9). However, the genes encoding anion efflux channels in plant plasma membranes remain unknown. Here we report the isolation of an Arabidopsis gene, SLAC1 ( SLOW ANION CHANNEL-ASSOCIATED 1, At1g12480), which mediates CO2 sensitivity in regulation of plant gas exchange. The SLAC1 protein is a distant homologue of bacterial and fungal C4- dicarboxylate transporters, and is localized specifically to the plasma membrane of guard cells. It belongs to a protein family that in Arabidopsis consists of four structurally related members that are common in their plasma membrane localization, but show distinct tissue- specific expression patterns. The loss- of- function mutation in SLAC1 was accompanied by an over- accumulation of the osmoregulatory anions in guard cell protoplasts. Guard- cell- specific expression of SLAC1 or its family members resulted in restoration of the wild- type stomatal responses, including CO2 sensitivity, and also in the dissipation of the over- accumulated anions. These results suggest that SLAC1-family proteins have an evolutionarily conserved function that is required for the maintenance of organic/ inorganic anion homeostasis on the cellular level.
  NATURE PUBLISHING GROUP, English
  DOI：https://doi.org/10.1038/nature06720
  DOI ID：10.1038/nature06720, ISSN：0028-0836, CiNii Articles ID：80019383908, PubMed ID：18305482, Web of Science ID：WOS:000254341300034
• The cell death factor, cell wall elicitor of rice blast fungus (Magnaporthe grisea) causes metabolic alterations including GABA shunt in rice cultured cells　　　　　　　　　　　　　　　
  Hideyuki Takahashi; Hideo Matsumura; Maki Kawai-Yamada; Hirofumi Uchimiya
  Plant Signaling and Behavior, Volume：3, Number：11, First page：945, Last page：953, 2008
  An elicitor derived from the cell wall of rice blast fungus (Magnaporthe grisea) causes cell death in suspension cultured cells of rice (Oryza sativa L.). To elucidate the role of M. grisea elicitor on metabolic pathway of rice cells, we performed metabolite profiling using capillary electrophoresis-mass spectrometry (CE/MS). Treatment with M. grisea elicitor increased the amounts of antioxidants and free amino acids and decreased the amount of metabolites in the tricarboxylic acid (TCA) cycle. Lower ATP concentration caused aberrant energy charge, concurrently with reduced amount of NAD(P)H in elicitor treated cells. Among free amino acids detected in this study, the level of gamma-aminobutyric acid (GABA) increased. GABA is metabolized through a bypass pathway of the TCA cycle called GABA shunt, which is composed of glutamate decarboxylase (GAD), GABA transaminase (GABA-T) and succinic semialdehyde dehydrogenase (SSADH). While M. grisea elicitor negligibly affected GAD and SSADH, GABA-T activity significantly decreased. The decrease in GABA-T activity was recovered by NADPH oxidase inhibitor, which prevents cell death induced by M. grisea elicitor. Thus, GABA accumulation observed in rice cells under elicitor stress is partly associated with GABA-T activity. ©2008 Landes Bioscience.
  Landes Bioscience, English
  DOI：https://doi.org/10.4161/psb.6112
  DOI ID：10.4161/psb.6112, ISSN：1559-2324, SCOPUS ID：56049093502
• The bax inhibitor-1 needs a functional electron transport chain for cell death suppression　　　　　　　　　　　　　　　
  Reiko Oshima; Keiko Yoshinaga; Yuri Ihara-Hori; Ryouichi Fukuda; Akinori Ohta; Hirofumi Uchimiya; Maki Kawai-Yamada
  FEBS LETTERS, Volume：581, Number：24, First page：4627, Last page：4632, Oct. 2007
  Bax inhibitor-1 (BI-1) is an evolutionarily conserved cell death suppresser in animals, yeast, and plants. In this study, yeast strains carrying single-gene deletions were screened for factors related to cell death suppression by Arabidopsis BI-1 (AtBI-1). Our screen identified mutants that failed to survive Bax-induced lethality even with AtBI-1 coexpression (Bax suppressor). The Delta cox16 strain was isolated as a BI-1-inactive mutant; it was disrupted in a component of the mitochondrial cytochrome c oxidase. Other mutants defective in mitochondrial electron transport showed a similar phenotype. ATP levels were markedly decreased in all these mutants, suggesting that BI-1 requires normal electron transport activity to suppress cell death in yeast. (c) 2007 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.
  ELSEVIER SCIENCE BV, English
  DOI：https://doi.org/10.1016/j.febslet.2007.08.054
  DOI ID：10.1016/j.febslet.2007.08.054, ISSN：0014-5793, CiNii Articles ID：80018237639, PubMed ID：17825821, Web of Science ID：WOS:000250102900014
• Arabidopsis thaliana nicotinate/nicotinamide mononucleotide adenyltransferase (AtNMNAT) is required for pollen tube growth　　　　　　　　　　　　　　　
  Shin-nosuke Hashida; Hideyuki Takahashi; Maki Kawai-Yamada; Hirofumi Uchimiya
  PLANT JOURNAL, Volume：49, Number：4, First page：694, Last page：703, Feb. 2007
  While mammals and fungi possess nicotinate/nicotinamide mononucleotide adenyltransferase (NMNAT) isoforms, Arabidopsis thaliana only contains a single NMNAT gene, AtNMNAT (At5g55810). We analyzed the enzymatic activity of the AtNMNAT-encoded protein to determine the role of AtNMNAT in plant development. AtNMNAT catalyzed the synthesis of nicotinate adenine dinucleotide (NaAD) from nicotinate mononucleotide (NaMN) in the Preiss-Handler-dependent pathway, and of nicotinamide adenine dinucleotide (NAD) from nicotiamide mononucleotide (NMN) in the Preiss-Handler-independent pathway. Prominent AtNMNAT expression was detected in the male gametophyte. Moreover, AtNMNAT expression was spatio-temporally regulated during microspore development and pollen tube growth. Disruption of the AtNMNAT gene (atnmnat mutant) was characterized by a decrease in NAD content in pollen. Cytological examinations revealed that the atnmnat mutant was gametophytically impaired in in vivo and in vitro pollen tube growth. Our results suggest that metabolic fulfillment via the NAD pathway is indispensable for normal pollen growth and subsequent normal seed production.
  BLACKWELL PUBLISHING, English
  DOI：https://doi.org/10.1111/j.1365-313X.2006.02989.x
  DOI ID：10.1111/j.1365-313X.2006.02989.x, ISSN：0960-7412, Web of Science ID：WOS:000244060500010
• Mutual regulation of Arabidopsis thaliana ethylene-responsive element binding protein and a plant floral homeotic gene, APETALA2　　　　　　　　　　　　　　　
  Taro Ogawa; Hirofumi Uchimiya; Maki Kawai-Yamada
  ANNALS OF BOTANY, Volume：99, Number：2, First page：239, Last page：244, Feb. 2007
  Background and Aims It has previously been shown that Arabidopsis thaliana ethylene-responsive element binding protein (AtEBP) contributed to resistance to abiotic stresses. Interestingly, it has also been reported that expression of ethylene-responsive factor (ERF) genes including AtEBP were regulated by the activity of APETALA2 (AP2), a floral homeotic factor. AP2 is known to regulate expression of several floral-specific homeotic genes such as AGAMOUS. The aim of this study was to clarify the relationship between AP2 and AtEBP in Gene expression.
  Methods Northern blot analysis was performed on ap2 mutants, ethylene-related Arabidopsis mutants and transgenic Arabidopsis plants over-expressing AtEBP, and a T-DNA insertional mutant of AtEBP. Phenotypic analysis of these plants was performed.
  Key Results Expression levels of ERF genes such as AtEBP and AtERF1 were increased in ap2 mutants. Over-expression of AtEBP caused upregulation of AP2 expression in leaves. AP2 expression was suppressed by the null-function of ethylene-insensitive2 (EIN2), although AP2 expression was not affected by ethylene treatment. Loss of AtEBP function slightly reduced the average number of stamens.
  Conclusions AP2 and AtEBP are mutually regulated in terms of gene expression. AP2 expression was affected by EIN2 but was not regulated by ethylene treatment.
  OXFORD UNIV PRESS, English
  DOI：https://doi.org/10.1093/aob/mcl265
  DOI ID：10.1093/aob/mcl265, ISSN：0305-7364, PubMed ID：17204538, Web of Science ID：WOS:000244566000004
• Cell death suppressor Arabidopsis Bax inhibitor-1 is associated with calmodulin binding and ion homeostasis　　　　　　　　　　　　　　　
  Yuri Ihara-Ohori; Minoru Nagano; Shoshi Muto; Hirofumi Uchimiya; Maki Kawai-Yamada
  PLANT PHYSIOLOGY, Volume：143, Number：2, First page：650, Last page：660, Feb. 2007
  Cell death suppressor Bax inhibitor-1 (BI-1), an endoplasmic reticulum membrane protein, exists in a wide range of organisms. The split-ubiquitin system, overlay assay, and bimolecular fluorescence complementation analysis demonstrated that Arabidopsis (Arabidopsis thaliana) BI-1 (AtBI-1) interacted with calmodulin in yeast (Saccharomyces cerevisiae) and in plant cells. Furthermore, AtBI-1 failed to rescue yeast mutants lacking Ca2+ ATPase (Pmr1 or Spf1) from Bax-induced cell death. Pmr1 and Spf1, p-type ATPases localized at the inner membrane, are believed to be involved in transmembrane movement of calcium ions in yeast. Thus, the presence of intact Ca2+ ATPases was essential for AtBI-1-mediated cell death suppression in yeast. To investigate the effect of AtBI-1 on calcium homeostasis, we evaluated sensitivity against cyclopiazonic acid (CPA), an inhibitor of sarcoplasmic/endoplasmic reticulum Ca2+ ATPase in AtBI-1-overexpressing or knock-down transgenic Arabidopsis plants. These plants demonstrated altered CPA or ion stress sensitivity. Furthermore, AtBI-1-overexpressing cells demonstrated an attenuated rise in cytosolic calcium following CPA or H2O2 treatment, suggesting that AtBI-1 affects ion homeostasis in plant cell death regulation.
  AMER SOC PLANT BIOLOGISTS, English
  DOI：https://doi.org/10.1104/pp.106.090878
  DOI ID：10.1104/pp.106.090878, ISSN：0032-0889, CiNii Articles ID：80017879340, PubMed ID：17142482, Web of Science ID：WOS:000244032400011
• Chloroplast NADK is necessary for regulation of carbon and nitrate metabolism　　　　　　　　　　　　　　　
  Hideyuki Takahashi; Sin-nosuke Hashida; Ayumi Tanaka; Kintake Sonoike; Maki Kawai; Hirofumi Uchimiya
  PLANT AND CELL PHYSIOLOGY, Volume：48, First page：S43, Last page：S43, 2007
  OXFORD UNIV PRESS, English, Summary international conference
  ISSN：0032-0781, Web of Science ID：WOS:000245922700167
• Chloroplast NAD kinase is essential for energy transduction through the xanthophyll cycle in photosynthesis　　　　　　　　　　　　　　　
  Hideyuki Takahashi; Ayako Watanabe; Ayumi Tanaka; Shin-nosuke Hashida; Maki Kawai-Yamada; Kintake Sonoike; Hirofumi Uchimiya
  PLANT AND CELL PHYSIOLOGY, Volume：47, Number：12, First page：1678, Last page：1682, Dec. 2006
  Photosynthetic parameters of the nadk2 mutant of Arabidopsis thaliana, which is defective in chloroplast NAD kinase, were investigated. In this plant, the effective efficiency of photosynthetic electron transport (Phi II) and the quantum yield of open reaction centers of photosystem II (Fv'/Fm') were decreased. Furthermore, an increase in nonphotochemical quenching attributed to energy dissipation from the xanthophyll cycle was observed. The mutant showed an aberrant de-epoxidation state of xanthophyll cycle carotenoids and had a high level of zeaxanthin even under low light conditions. These results indicate that chloroplast NAD kinase, catalyzing phosphorylation of NAD, is essential for the proper photosynthetic machinery of PSII and the xanthophyll cycle.
  OXFORD UNIV PRESS, English
  DOI：https://doi.org/10.1093/pcp/pcl029
  DOI ID：10.1093/pcp/pcl029, ISSN：0032-0781, CiNii Articles ID：10018809609, PubMed ID：17082216, Web of Science ID：WOS:000243131300010
• Evaluation of metabolic alteration in transgenic rice overexpressing dihydroflavonol-4-reductase　　　　　　　　　　　　　　　
  Hideyuki Takahashi; Mitsunori Hayashi; Fumiyuki Goto; Shigeru Sato; Tomoyoshi Soga; Takaaki Nishioka; Masaru Tomita; Maki Kawai-Yamada; Hirofumi Uchimiya
  ANNALS OF BOTANY, Volume：98, Number：4, First page：819, Last page：825, Oct. 2006
  center dot Background and Aims Previous studies have shown that transgenic rice plants overexpressing YK1, which possesses dihydroflavonol-4-reductase (DFR) activity, showed biotic and abiotic stress tolerance. High throughput profiles of metabolites have also been shown in such transgenic plants by Fourier transform ion cyclotron mass spectrometry. In this study, capillary electrophoresis mass spectrometry analysis (CE/MS) was employed to identify precise metabolites such as organic acids, amino acids and sugars.
  center dot Methods Using CE/MS, we analysed several metabolites of glycolysis, the tricarboxylic acid (TCA) cycle and the pentose phosphate pathway. In addition, the concentrations of sugars and ion were quantified.
  center dot Key Results In YK1 (DFR)-overexpressing plants, the concentrations of cis-aconitate, isocitrate and 2-oxoglutarate were higher in leaves, whereas those of fructose-1,6-bisphosphate and glyceraldehyde-3-phosphate were lower in roots. In seeds, the amounts of free amino acids and metals were altered, whereas sugars in seeds were kept constant. In YK1 calli, an approx. 3-fold increase in glutathione was observed, whereas the activities of glutathione peroxidase and glutathione reductase were concomitantly increased.
  center dot Conclusions The overexpression of YK1 (DFR) was associated with slight changes in the amounts of several metabolites analysed in whole plants, whilst glutathione derivatives were substantially increased in suspension-cultured cells.
  OXFORD UNIV PRESS, English
  DOI：https://doi.org/10.1093/aob/mcl162
  DOI ID：10.1093/aob/mcl162, ISSN：0305-7364, eISSN：1095-8290, CiNii Articles ID：30022963309, PubMed ID：16849376, Web of Science ID：WOS:000240925800010
• Abolition of the tapetum suicide program ruins microsporogenesis　　　　　　　　　　　　　　　
  Takahiro Kawanabe; Tohru Ariizumi; Maki Kawai-Yamada; Hirofumi Uchimiya; Kinya Toriyama
  PLANT AND CELL PHYSIOLOGY, Volume：47, Number：6, First page：784, Last page：787, Jun. 2006
  Microsporogenesis in angiosperms takes places within the anther. Microspores are surrounded by a layer of cells, the tapetum, which degenerates during the later stages of pollen development with cytological features characteristic of programmed cell death (PCD). We report herein that the expression of AtBI-1, which suppresses Bax-induced cell death, in the tapetum at the tetrad stage inhibits tapetum degeneration and subsequently results in pollen abortion, while activation of AtBI-1 at the later stage does not. Our results demonstrate that the PCD signal commences at the tetrad stage and that the proper timing of PCD in the tapetum is essential for normal microsporogenesis.
  OXFORD UNIV PRESS, English
  DOI：https://doi.org/10.1093/pcp/pcj039
  DOI ID：10.1093/pcp/pcj039, ISSN：0032-0781, CiNii Articles ID：10017602383, PubMed ID：16565524, Web of Science ID：WOS:000238538300013
• The mitochondrial fission regulator DRP3B does not regulate cell death in plants　　　　　　　　　　　　　　　
  Keiko Yoshinaga; Masaru Fujimoto; Shin-ichi Arimura; Nobuhiro Tsutsumi; Hirofumi Uchimiya; Maki Kawai-Yamada
  ANNALS OF BOTANY, Volume：97, Number：6, First page：1145, Last page：1149, Jun. 2006
  e Background and Aims Recent reports have described dramatic alterations in mitochondrial morphology during metazoan apoptosis. A dynamin-related protein (DRP) associated with mitochondrial outer membrane fission is known to be involved in the regulation of apoptosis. This study analysed the relationship between mitochondrial fission and regulation of plant cell death.
  center dot Methods Transgenic plants were generated possessing Arabidopsis DRP3B (K56A), the dominant-negative form of Arabidopsis DRP, mitochondrial-targeted green fluorescent protein and mouse Bax.
  center dot Key Results Arabidopsis plants over-expressing DRP3B (K56A) exhibited long tubular mitochondria. In these plants, mitochondria appeared as a string-of-beads during cell death. This indicates that DRP3B (K56A) prevented mitochondrial fission during plant cell death. However, in contrast to results for mammalian cells and yeast, Bax-induced cell death was not inhibited in DRP3B (K56A)-expressing plant cells. Similarly, hydrogen peroxide-, menadione, darkness- and salicylic acid-induced cell death was not inhibited by DRP3B (K56A) expression.
  center dot Conclusions These results indicate that the systems controlling cell death in animals and plants are not common in terms of mitochondrial fission.
  OXFORD UNIV PRESS, English
  DOI：https://doi.org/10.1093/aob/mcl057
  DOI ID：10.1093/aob/mcl057, ISSN：0305-7364, eISSN：1095-8290, CiNii Articles ID：10027345732, PubMed ID：16533833, Web of Science ID：WOS:000238816800023
• Arabidopsis transcriptional factor, AtEBP inhibited the hypersensitive response mediated by Pseudomonas syringae with an avirulent gene　　　　　　　　　　　　　　　
  T Ogawa; K Tamura; M Kawai; H Uchimiya
  PLANT AND CELL PHYSIOLOGY, Volume：47, First page：S47, Last page：S47, 2006
  OXFORD UNIV PRESS, English, Summary international conference
  ISSN：0032-0781, Web of Science ID：WOS:000236401400186
• Analysis of calmodulin interacting with cell death suppressor (AtBI-1)　　　　　　　　　　　　　　　
  Z Hori; Y Ohori; H Uchimiya; M Kawai
  PLANT AND CELL PHYSIOLOGY, Volume：47, First page：S43, Last page：S43, 2006
  OXFORD UNIV PRESS, English, Summary international conference
  ISSN：0032-0781, Web of Science ID：WOS:000236401400170
• A novel Arabidopsis gene causes Bax-like lethality in Saccharomyces cerevisiae　　　　　　　　　　　　　　　
  M Kawai-Yamada; Y Saito; LH Jin; T Ogawa; KM Kim; LH Yu; Y Tone; A Hirata; M Umeda; H Uchimiya
  JOURNAL OF BIOLOGICAL CHEMISTRY, Volume：280, Number：47, First page：39468, Last page：39473, Nov. 2005
  Overexpression of the mammalian proapoptotic protein Bax induces cell death in plant and yeast cells. The Bax inihibitor-1 (BI-1) gene rescues yeast and plant from Bax-mediated lethality. Using the Arabidopsis BI-1 (AtBI-1) gene controlled by the GAL1 promoter as a cell death suppressor in yeast, Cdf1 ((c) under bar ell growth (d) under bar efect (f) under bar actor-(1) under bar) was isolated from Arabidopsis cDNA library. Overexpression of Cdf1 caused cell death in yeast, whereas such an effect was suppressed by co-expression of AtBI-1. The Cdf1 protein fused with a green fluorescent protein was localized in the mitochondria and resulted in the loss of mitochondrial membrane potential in yeast. The Bax-resistant mutant BRM1 demonstrated tolerance against Cdf1-mediated lethality, whereas the Delta atp4 strain was sensitive to Cdf1. Our results suggest that Cdf1 and Bax cause mitochondria-mediated yeast lethality through partially overlapped pathways.
  AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC, English
  DOI：https://doi.org/10.1074/jbc.M509632200
  DOI ID：10.1074/jbc.M509632200, ISSN：0021-9258, CiNii Articles ID：80017727608, PubMed ID：16192270, Web of Science ID：WOS:000233362200068
• Mammalian Bax initiates plant cell death through organelle destruction　　　　　　　　　　　　　　　
  K Yoshinaga; S Arimura; A Hirata; Y Niwa; DJ Yun; N Tsutsumi; H Uchimiya; M Kawai-Yamada
  PLANT CELL REPORTS, Volume：24, Number：7, First page：408, Last page：417, Sep. 2005
  Mammalian Bax is known to cause cell death when expressed in plants. We examined transgenic plants expressing both Bax and organelle-targeted green fluorescent protein to determine the cellular changes that occur during Bax-induced cell death. The mitochondria changed morphologically from being bacilli-shaped to being round, eventually becoming swollen. Mitochondria streaming also stopped. The chloroplasts lost membrane function and their contents leaked out, followed by the disruption of the vacuole. Light was not essential for Bax-induced ion leakage or organelle disruption. These results indicate that Bax induces temporal and spatial cell death events at the organelle level in the plant. A heterologous system, using Bax, would therefor be available to investigate cell death, which is commonly conserved in animals and plants.
  SPRINGER, English
  DOI：https://doi.org/10.1007/s00299-005-0948-6
  DOI ID：10.1007/s00299-005-0948-6, ISSN：0721-7714, Web of Science ID：WOS:000232223000004
• Mitochondrial behaviour in the early stages of ROS stress leading to cell death in Arabidopsis thaliana　　　　　　　　　　　　　　　
  K Yoshinaga; SI Arimura; Y Niwa; N Tsutsumi; H Uchimiya; M Kawai-Yamada
  ANNALS OF BOTANY, Volume：96, Number：2, First page：337, Last page：342, Aug. 2005
  Background and Aims Reactive oxygen species (ROS) are involved in triggering cell death. To visualize mitochondrial behaviour under ROS stress, transgenic arabidopsis plants possessing mitochondrial-targeted GFP ( S65T) were studied.
  Methods Arabidopsis leaves were treated with ROS and ROS-inducing chemicals such as hydrogen peroxide, paraquat and menadione. Microscopic observations were carried out using a confocal laser scanning microscope system, and electrolyte leakage was also monitored.
  Key Results After treatment, mitochondria showed morphological changes from a bacillus- like to a round shape. The size of mitochondria treated with H2O2 decreased by half compared with controls. Concurrently, cytoplasmic streaming was blocked and mitochondria eventually swelled. Treatment of leaves with butanedione monoxime, an inhibitor of myosin ATPase, resulted in similar behaviour of mitochondria to that under ROS stress.
  Conclusions The results indicate that morphological changes of mitochondria and cessation of cytoplasmic streaming may interact, and this phenomenon is one of the features of ROS stress-induced cell death.
  OXFORD UNIV PRESS, English
  DOI：https://doi.org/10.1093/aob/mci181
  DOI ID：10.1093/aob/mci181, ISSN：0305-7364, Web of Science ID：WOS:000230724400018
• Functional analysis of Arabidopsis ethylene-responsive element binding protein conferring resistance to Bax and abiotic stress-induced plant cell death　　　　　　　　　　　　　　　
  T Ogawa; L Pan; M Kawai-Yamada; LH Yu; S Yamamura; T Koyama; S Kitajima; M Ohme-Takagi; F Sato; H Uchimiya
  PLANT PHYSIOLOGY, Volume：138, Number：3, First page：1436, Last page：1445, Jul. 2005
  Arabidopsis ( Arabidopsis thaliana) ethylene-responsive element binding protein ( AtEBP) gene was isolated as a suppressor of Bax-induced cell death by functional screening in yeast ( Saccharomyces cerevisiae). To further examine the cell death suppressive action of AtEBP in plant cells, we established transgenic tobacco ( Nicotiana tabacum) plants overexpressing AtEBP as well as transgenic tobacco plants ectopically expressing mouse Bax protein under a dexamethasone-inducible promoter. We prepared the crosses of the selective lines of each transgenic plant, which were evaluated in terms of cell death suppression activity. Results indicate that AtEBP suppressed Bax- induced cell death in tobacco plants, an action also associated with a lowered level of ion leakage. Furthermore, tobacco Bright Yellow-2 cells overexpressing AtEBP conferred resistance to hydrogen peroxide ( H2O2) and heat treatments. AtEBP protein localized in the nucleus and functioned as an in vivo transcription activator as confirmed in transient assays and experiments using stable transgenic system. Up-regulation of defense genes was observed in transgenic Arabidopsis plants overexpressing AtEBP. Based on the analysis of mRNA accumulation in ethylene-related mutants, the position of AtEBP in signaling pathway is presented.
  AMER SOC PLANT BIOLOGISTS, English
  DOI：https://doi.org/10.1104/pp.105.063586
  DOI ID：10.1104/pp.105.063586, ISSN：0032-0889, CiNii Articles ID：80017583019, PubMed ID：15980186, Web of Science ID：WOS:000230414800024
• Enhanced dihydroflavonol-4-reductase activity and NAD homeostasis leading to cell death tolerance in transgenic rice　　　　　　　　　　　　　　　
  M Hayashi; H Takahashi; K Tamura; Huang, JR; LH Yu; M Kawai-Yamada; T Tezuka; H Uchimiya
  PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, Volume：102, Number：19, First page：7020, Last page：7025, May 2005
  The maize Hm1 gene encoding the NADPH-dependent HC-toxin reductase is capable of detoxifying HC-toxin of fungus Cochliobolus carbonum. Here, we conducted the metabolic and biochemical analysis in transgenic rice plants overexpressing an HC-toxin reductase-like gene in rice (YK1 gene). Methods employing NADPH oxidation and capillary electrophoresis mass spectrometry analysis confirmed that YK1 possessed dihydroflavonol-4-reductase activity in vitro and in vivo. The overexpression of YK1 in both suspension-cultured cells and rice plants increased NAD(H) and NADP(H) levels by causing an increase in NAD synthetase and NAD kinase activities. Activity changes in enzymes that require NAD(P) as coenzymes were also noted in rice cells ectopically expressing YK1, where the cell death caused by hydrogen peroxide and bacterial disease was down-regulated. Thus, a strategy was proposed that the combination of dihydroflavonol-4-reductase activity and the elevated level of NAD(P)H pool may confer the prevention of induced cell death in planta.
  NATL ACAD SCIENCES, English
  DOI：https://doi.org/10.1073/pnas.0502556102
  DOI ID：10.1073/pnas.0502556102, ISSN：0027-8424, CiNii Articles ID：80017290330, PubMed ID：15863611, Web of Science ID：WOS:000229048500068
• Analysis of mitochondrial changes in Arabidopsis thaliana during ROS induced cell death　　　　　　　　　　　　　　　
  K Yoshinaga; M Kawai; S Arimura; M Fujimoto; N Tsutsumi; H Uchimiya
  PLANT AND CELL PHYSIOLOGY, Volume：46, First page：S200, Last page：S200, 2005
  OXFORD UNIV PRESS, English, Summary international conference
  ISSN：0032-0781, Web of Science ID：WOS:000228104101303
• The stress response of Arabidopsis transcriptional factor AtEBP　　　　　　　　　　　　　　　
  T Ogawa; LH Yu; M Kawai; H Uchimiya
  PLANT AND CELL PHYSIOLOGY, Volume：46, First page：S199, Last page：S199, 2005
  OXFORD UNIV PRESS, English, Summary international conference
  ISSN：0032-0781, Web of Science ID：WOS:000228104101300
• Maize plants mutated in NAD(P)H-dependent HC-toxin reductase gene (Hm1) is vulnerable to H2O2 stress　　　　　　　　　　　　　　　
  Mitsunori Hayashi; Hideyuki Takahashi; Maki Kawai-Yamada; Takafumi Tezuka; Hirofumi Uchimiya
  Plant Biotechnology, Volume：22, Number：1, First page：69, Last page：70, 2005
  Maize Hm1 gene encodes a NAD(P)H-dependent HC-toxin reductase, which detoxify HC-toxin produced by fungus Cochliobolus carbonum (Meeley and Walton 1991 Plant Phys 97: 1080). Measurements of ion leakage indicated that H 2O2 treatment of a recessive mutant (hm1) of maize resulted in accelerated death in excised leaves. Furthermore, an hm1 maize showed quantitative decrease of NAD(H) level. Thus, the Hm1 gene may confer other functions related to ROS stress tolerance. Copyright © 2005 The Japanese Society for Plant Cell and Molecular Biology.
  Japanese Society for Plant Cell and Molecular Biology, English
  DOI：https://doi.org/10.5511/plantbiotechnology.22.69
  DOI ID：10.5511/plantbiotechnology.22.69, ISSN：1347-6114, CiNii Articles ID：10026526470, SCOPUS ID：18744402810
• High throughput metabolome and proteome analysis of transgenic rice plants (Oryza sativa L.)　　　　　　　　　　　　　　　
  Hideyuki Takahashi; Yuji Hotta; Mitsunori Hayashi; Maki Kawai-Yamada; Setsuko Komatsu; Hirofumi Uchimiya
  Plant Biotechnology, Volume：22, Number：1, First page：47, Last page：50, 2005
  We profiled metabolic patterns of transgenic rice organs and tissue by Fourier-transform ion cyclotron mass spectrometry (FT-MS) to reveal effects of the over-expression of repossessing high homology with maize HC-toxin reductase gene. Comparison of metabolic patterns revealed that compositions of organ- or tissue-specific metabolites were not significantly varied between the control and the YK1 rice, where expression levels of some metabolites were altered. Proteome analysis of cultured cells over-expressing YK1 showed the up-regulation of several stress-related proteins such as osmotin-like protein and osr40c1. Thus, alteration of metabolites as well as proteins may contribute to multiple stress tolerances in transgenic YK1 rice. Copyright © 2005 The Japanese Society for Plant Cell and Molecular Biology.
  Japanese Society for Plant Cell and Molecular Biology, English
  DOI：https://doi.org/10.5511/plantbiotechnology.22.47
  DOI ID：10.5511/plantbiotechnology.22.47, ISSN：1347-6114, CiNii Articles ID：10026526399, SCOPUS ID：18744410743
• Oxidative stress and plant cell death suppressors　　　　　　　　　　　　　　　
  Maki Kawai-Yamada; Keiko Yoshinaga; Taro Ogawa; Yuri Ihara-Ohori; Hirofumi Uchimiya
  Plant Biotechnology, Volume：22, Number：5, First page：419, Last page：422, 2005
  Classical yeast genetic approaches have been successfully applied for identification of genes related to the suppression of cell death. Isolated genes included several reactive oxygen species (ROS)-related genes such as SOD (superoxide dismutase), peroxidase, and GST (glutathione S-transferase). The AtBI-1 (Arabidopsis Bax Inhibitor-1), which is a plant homolog of mammalian antiapoptotic gene BI-1, was also isolated as a suppressor of Bax-mediated lethality in yeast. Overexpression of BI-1 suppresses Bax-, H2O 2-, salicylic acid-, and elicitor- induced cell death in plant cells. These data indicate conserved overlapping pathways that regulate ROS-mediated cell death in plants and animals.
  Japanese Society for Plant Cell and Molecular Biology, English, Book review
  DOI：https://doi.org/10.5511/plantbiotechnology.22.419
  DOI ID：10.5511/plantbiotechnology.22.419, ISSN：1347-6114, CiNii Articles ID：10028054734, SCOPUS ID：30344438808
• Isolation and characterization of Arabidopsis thaliana ISU1 gene　　　　　　　　　　　　　　　
  Y Tone; M Kawai-Yamada; H Uchimiya
  BIOCHIMICA ET BIOPHYSICA ACTA-GENE STRUCTURE AND EXPRESSION, Volume：1680, Number：3, First page：171, Last page：175, Nov. 2004
  We describe the isolation of a cDNA encoding Arabidopsis thaliana ISU1 (AtISU1), which regulates iron homeostasis in the mitochondria. The AtISU1 gene contained an open reading frame that encoded 167 amino acid residues. Northern blot analysis demonstrated that AtISU1 gene was ubiquitously expressed in plant tissues examined. The yeast seo5-1, which harbors a single base-pair deletion in ScISU1, is a suppressor of oxidative damage in sod1-deficient mutant. Based on comparative expression analyses using yeast ISU1 gene (ScISU1) in seo5-1 mutant, we found that AtISU1 acts as a counterpart of ScISU1. (C) 2004 Elsevier B.V. All rights reserved.
  ELSEVIER SCIENCE BV, English
  DOI：https://doi.org/10.1016/j.bbaexp.2004.09.005
  DOI ID：10.1016/j.bbaexp.2004.09.005, ISSN：0167-4781, Web of Science ID：WOS:000224938300004
• Bax-induced cell death of Arabidopsis is meditated through reactive oxygen-dependent and -independent processes　　　　　　　　　　　　　　　
  D Baek; J Nam; YD Koo; DH Kim; J Lee; JC Jeong; SS Kwak; WS Chung; CO Lim; JD Bahk; JC Hong; SY Lee; M Kawai-Yamada; H Uchimiya; DJ Yun
  PLANT MOLECULAR BIOLOGY, Volume：56, Number：1, First page：15, Last page：27, Sep. 2004
  An Arabidopsis protoplast system was developed for dissecting plant cell death in individual cells. Bax, a mammalian pro-apoptotic member of the Bcl-2 family, induces apoptotic-like cell death in Arabidopsis. Bax accumulation in Arabidopsis mesophyll protoplasts expressing murine Bax cDNA from a glucocorticoid-inducible promoter results in cytological characteristics of apoptosis, namely DNA fragmentation, increased vacuolation, and loss of plasma membrane integrity. In vivo targeting analysis monitored using jellyfish green fluorescent protein (GFP) reporter indicated full-length Bax was localized to the mitochondria, as it does in animal cells. Deletion of the carboxyl-terminal transmembrane domain of Bax completely abolished targeting to mitochondria. Bax expression was followed by reactive oxygen species (ROS) accumulation. Treatment of protoplasts with the antioxidant N-acetyl-L-cysteine (NAC) during induction of Bax expression strongly suppressed Bax-mediated ROS production and the cell death phenotype. However, some population of the ROS depleted cells still induced cell death, indicating that there is a process that Bax-mediated plant cell death is independent of ROS accumulation. Accordingly, suppression of Bax-mediated plant cell death also takes place in two different processes. Over-expression of a key redox-regulator, Arabidopsis nucleoside diphosphate kinase 2 (AtNDPK2) down-regulated ROS accumulation and suppressed Bax-mediated cell death and transient expression of Arabidopsis Bax inhibitor-1 (AtBI-1) substantially suppressed Bax-induced cell death without altering cellular ROS level. Taken together, our results collectively suggest that the Bax-mediated cell death and its suppression in plants is mediated by ROS-dependent and -independent processes.
  KLUWER ACADEMIC PUBL, English
  DOI：https://doi.org/10.1007/s11103-004-3096-4
  DOI ID：10.1007/s11103-004-3096-4, ISSN：0167-4412, CiNii Articles ID：10028054735, PubMed ID：15604726, Web of Science ID：WOS:000225899900002
• Analysis of functional domains of cell death suppressor (AtBI-1)　　　　　　　　　　　　　　　
  Y Ohori; M Kawai; H Uchimiya
  PLANT AND CELL PHYSIOLOGY, Volume：45, First page：S62, Last page：S62, 2004
  OXFORD UNIV PRESS, English, Summary international conference
  ISSN：0032-0781, Web of Science ID：WOS:000220592700244
• Functional analysis of Arabidopsis AtEBP in plants and stress responses　　　　　　　　　　　　　　　
  T Ogawa; LH Yu; M Ohme-Takagi; F Sato; M Kawai; H Uchimiya
  PLANT AND CELL PHYSIOLOGY, Volume：45, First page：S50, Last page：S50, 2004
  OXFORD UNIV PRESS, English, Summary international conference
  ISSN：0032-0781, Web of Science ID：WOS:000220592700198
• Screening of Arabidopsis genes capable of inducing yeast cell death　　　　　　　　　　　　　　　
  M Kawai; Y Saitoh; K Yoshinaga; H Uchimiya
  PLANT AND CELL PHYSIOLOGY, Volume：45, First page：S62, Last page：S62, 2004
  OXFORD UNIV PRESS, English, Summary international conference
  ISSN：0032-0781, Web of Science ID：WOS:000220592700245
• Dissection of Arabidopsis Bax inhibitor-1 suppressing Bax-, hydrogen peroxide-, and salicylic acid-induced cell death　　　　　　　　　　　　　　　
  M Kawai-Yamada; Y Ohori; H Uchimiya
  PLANT CELL, Volume：16, Number：1, First page：21, Last page：32, Jan. 2004
  Overexpression of plant Bax Inhibitor-1 (BI-1) was able to suppress Bax-mediated cell death in yeast and Arabidopsis. Here, we demonstrate that reactive oxygen species production induced by the ectopic expression of Bax was insensitive to the coexpression of AtBI-1. Similarly, H2O2- or salicylic acid-mediated cell death also was suppressed in tobacco BY-2 cells overexpressing AtBI-1. To define the functional domain of AtBI-1 as a cell death suppressor, a truncated series of the AtBI-1 protein was analyzed in yeast possessing a galactose-inducible mammalian Bax. The results showed that DeltaC-AtBI-1 (with the C-terminal 14 amino acids deleted) lost the ability to sustain cell growth. Furthermore, a mutant protein in which the C-terminal seven amino acid residues of AtBI-1 were replaced with others lacking a coiled-coil structure failed to inhibit cell death, suggesting that the C-terminal region is essential for the inhibition of cell death. We also noted that the C-terminal hydrophilic region was interchangeable between animal and plant Bax inhibitors.
  AMER SOC PLANT BIOLOGISTS, English
  DOI：https://doi.org/10.1105/tpc.014613
  DOI ID：10.1105/tpc.014613, ISSN：1040-4651, CiNii Articles ID：80016434021, PubMed ID：14671021, Web of Science ID：WOS:000188229000003
• Overexpression of Bax inhibitor suppresses the fungal elicitor-induced cell death in rice (Oryza sativa L.) cells　　　　　　　　　　　　　　　
  H Matsumura; S Nirasawa; A Kiba; N Urasaki; H Saitoh; M Ito; M Kawai-Yamada; H Uchimiya; R Terauchi
  PLANT JOURNAL, Volume：33, Number：3, First page：425, Last page：434, Feb. 2003
  Treatment of suspension-cultured cells of rice (Oryza sativa L.) with cell wall extract of rice blast fungus (Magnaporthe grisea ) elicits a rapid generation of H2O2, alkalinization of culture medium, and eventual cell death. To elucidate genes involved in these processes, we exploited SAGE (Serial Analysis of Gene Expression) technique for the molecular analysis of cell death in suspension-cultured cells treated with the elicitor. Among the downregulated genes in the elicitor-treated cells, a BI-1 gene coding for Bax inhibitor was identified. Transgenic rice cells overexpressing Arabidopsis BI-1 gene showed sustainable cell survival when challenged with M. grisea elicitor. Thus, the plant Bax inhibitor plays a functional role in regulating cell death in the rice cell culture system.
  BLACKWELL PUBLISHING LTD, English
  DOI：https://doi.org/10.1046/j.1365-313X.2003.01639.x
  DOI ID：10.1046/j.1365-313X.2003.01639.x, ISSN：0960-7412, Web of Science ID：WOS:000180851300001
• A plant gene (AtBI-1) conferring elevated tolerance to ROS-induced cell death　　　　　　　　　　　　　　　
  M Kawai; H Uchimiya
  PLANT AND CELL PHYSIOLOGY, Volume：44, First page：S207, Last page：S207, 2003
  OXFORD UNIV PRESS, English, Summary international conference
  ISSN：0032-0781, Web of Science ID：WOS:000181914300821
• Cellular dissection of bax-induced cell death in plants　　　　　　　　　　　　　　　
  K Yoshinaga; M Kawai; H Uchimiya
  PLANT AND CELL PHYSIOLOGY, Volume：44, First page：S207, Last page：S207, 2003
  OXFORD UNIV PRESS, English, Summary international conference
  ISSN：0032-0781, Web of Science ID：WOS:000181914300820
• Glufosinate-tolerant tobacco plants directed by the promoter of adenylate kinase gene of rice　　　　　　　　　　　　　　　
  H Fukuzawa; S Arai; M Kawai-Yamada; A Das; M Tagawa; H Uchimiya
  ANNALS OF BOTANY, Volume：89, Number：3, First page：351, Last page：354, Mar. 2002
  A DNA clone containing the 5' part of the adenylate kinase (AK) gene was isolated from a rice genomic library, and its nucleotide sequence was determined. This clone consists of 5' upstream, five exons and four introns of the AK gene. All of the determined donor and receptor sites contained 'GT' and 'AG' consensus splice sequences. Transgenic tobacco plants harbouring a chimeric gene consisting of the 5' upstream sequence of the AK gene fused with the gene encoding phosphinothricin acetyl transferase were generated. They showed tolerance to glufosinate to a level four times higher than its commercial dose, (C) 2002 Annals of Botany Company.
  OXFORD UNIV PRESS, English
  DOI：https://doi.org/10.1093/aob2002mcf041
  DOI ID：10.1093/aob2002mcf041, ISSN：0305-7364, Web of Science ID：WOS:000174774500012
• Induction of mammalian cell death by a plant Bax inhibitor　　　　　　　　　　　　　　　
  LH Yu; M Kawai-Yamada; M Naito; K Watanabe; JC Reed; H Uchimiya
  FEBS LETTERS, Volume：512, Number：1-3, First page：308, Last page：312, Feb. 2002
  Arabidopsis thaliana AtBI-1 is an orthologue of mammalian Bax inhibitor-1 capable of suppressing Bax-induced cell death in yeast as well as mammalian cells. Here Ne investigated whether or not AtBI-1 suppresses Bax-induced cell death using human fibrosarcoma HT1080 cells. Surprisingly, AtBI-1 did not block Bax-induced cell death. but it triggered apoptotic cell death in mammalian cells. The proapoptotic effect of AtBI-I as blocked by the X-linked caspase inhibitor XIAP, suggesting that the cell death caused by AtBI-1 is similar to that caused by Bax. (C) 2002 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.
  ELSEVIER SCIENCE BV, English
  DOI：https://doi.org/10.1016/S0014-5793(02)02230-5
  DOI ID：10.1016/S0014-5793(02)02230-5, ISSN：0014-5793, CiNii Articles ID：80015200913, PubMed ID：11852101, Web of Science ID：WOS:000174081900061
• Down-regulation of mammalian bax-induced plant cell death by Arabidopsis Bax inhibitor-1 (AtBI-1)　　　　　　　　　　　　　　　
  M Kawai; H Uchimiya
  PLANT AND CELL PHYSIOLOGY, Volume：43, First page：S215, Last page：S215, 2002
  OXFORD UNIV PRESS, English, Summary international conference
  ISSN：0032-0781, Web of Science ID：WOS:000174726400757
• Transgenic rice plants conferring increased tolerance to rice blast and multiple environmental stresses　　　　　　　　　　　　　　　
  H Uchimiya; S Fujii; Huang, JR; T Fushimi; M Nishioka; KM Kim; MK Yamada; T Kurusu; K Kuchitsu; M Tagawa
  MOLECULAR BREEDING, Volume：9, Number：1, First page：25, Last page：31, 2002
  We isolated a rice gene (denoted YK1), which showed 78 percent amino acid sequence homology to the maize HM1 gene. A chimeric gene consisting of a promoter and first intron of maize ubiquitin gene and the cDNA of YK1 was introduced into rice via Agrobacterium mediated transformation. Transgenic rice plants overexpressing this chimeric gene were resistant to rice blast (Magnaporthe grisea) disease, which is one of the most serious pathogens in rice. Furthermore, the same transgenic plants conferred high tolerance to several abiotic stresses such as NaCl, UV-C, submergence, and hydrogen peroxide.
  SPRINGER, English
  DOI：https://doi.org/10.1023/A:1019275218830
  DOI ID：10.1023/A:1019275218830, ISSN：1380-3743, Web of Science ID：WOS:000176505700003
• The Arabidopsis thaliana ethylene-responsive element binding protein (AtEBP) can function as a dominant suppressor of Bax-induced cell death of yeast　　　　　　　　　　　　　　　
  L Pan; M Kawai; LH Yu; KM Kim; A Hirata; M Umeda; H Uchimiya
  FEBS LETTERS, Volume：508, Number：3, First page：375, Last page：378, Nov. 2001
  We identified genes based on screening of an Arabidopsis cDNA library for functional suppressors of mouse Bax-induced cell death of yeast cells. Interestingly, the cDNA encoding AtEBP, known as Arabidopsis thaliana ethylene-responsive element binding protein, was isolated numerous times in the functional screen (82% of all suppressors). Full-length AtEBP and its localization to the nucleus were essential for the suppression of Bax-induced cell death. Morphological abnormality of intracellular network that is a hallmark of Bax-induced cell death was attenuated by expression of AtEBP. (C) 2001 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.
  ELSEVIER SCIENCE BV, English
  DOI：https://doi.org/10.1016/S0014-5793(01)03098-8
  DOI ID：10.1016/S0014-5793(01)03098-8, ISSN：0014-5793, CiNii Articles ID：80012784681, PubMed ID：11728455, Web of Science ID：WOS:000172416300020
• Mammalian Bax-induced plant cell death can be down-regulated by overexpression of Arabidopsis Bax Inhibitor-1 (AtBl-1)　　　　　　　　　　　　　　　
  M Kawai-Yamada; LH Jin; K Yoshinaga; A Hirata; H Uchimiya
  PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, Volume：98, Number：21, First page：12295, Last page：12300, Oct. 2001
  We recently isolated the AtBI-1 (Arabidopsis Bax Inhibitor-1) gene, the expression of which suppressed Bax-induced cell death in yeast. To determine whether the same is true in the plant system, transgenic Arabidopsis plants overexpressing Bax protein under a dexamethasone (DEX)-inducible promoter were generated. On DEX treatment, such transgenic plants exhibited marked cell death at the whole-plant level, cell shrinkage, membranous destruction, and other apoptotic phenotypes. Transgenic Bax plants were retransformed with a vector containing the AtBI-1 gene (tagged with green fluorescent protein) under the control of the cauliflower mosaic virus 35S promoter. Plants expressing both Bax and AtBI-1 were able to maintain growth on DEX-treatment by sustaining intracellular integrity. Thus, we present here direct genetic evidence that the plant antiapoptotic protein AtBI-1 is biologically active in suppressing the mammalian Bax action in planta.
  NATL ACAD SCIENCES, English
  DOI：https://doi.org/10.1073/pnas.211423998
  DOI ID：10.1073/pnas.211423998, ISSN：0027-8424, CiNii Articles ID：80012776846, PubMed ID：11593047, Web of Science ID：WOS:000171558900085
• 植物の形態形成分子機構の研究 イオンビームによる植物細胞アポトーシス誘導体の確立
  川合真紀; 小林泰彦; 大野豊; 渡辺宏; 内宮博文
  基礎科学ノート, Volume：8, Number：1, First page：9, Last page：12, Mar. 2001
  Japanese
  ISSN：1340-3079, J-Global ID：200902118512698355
• Nucleoside diphosphate kinase required for coleoptile elongation in rice　　　　　　　　　　　　　　　
  L Pan; M Kawai; A Yano; H Uchimiya
  PLANT PHYSIOLOGY, Volume：122, Number：2, First page：447, Last page：452, Feb. 2000
  Although several nucleoside diphosphate (NDP) kinase genes have been cloned in plants, little is known about the functional significance of this enzyme during plant growth and development. We introduced a chimeric gene encoding an antisense RNA of NDP kinase under the control of the Arabidopsis heat shock protein HSP81-1 promoter into rice (Oryza sativa L.) plants using the Agrobacterium tumefaciens transformation system. The expression of antisense RNA down-regulated the accumulation of mRNA, resulting in reduced enzyme activity even under the standard growth temperature (25 degrees C) in transgenic plants. Following heat shock treatment (37 degrees C), NDP kinase activities in some transgenic rice plants were more reduced than those grown under 25 degrees C. The comparison of the coleoptile growth under submersion showed that cell elongation process was inhibited in antisense NDP kinase transgenic plants, suggesting that an altered guanine nucleotide level may be responsible for the processes.
  AMER SOC PLANT BIOLOGISTS, English
  DOI：https://doi.org/10.1104/pp.122.2.447
  DOI ID：10.1104/pp.122.2.447, ISSN：0032-0889, eISSN：1532-2548, CiNii Articles ID：80011516620, PubMed ID：10677437, Web of Science ID：WOS:000086903000014
• Coleoptile senescence in rice (Oryza sativa L.)　　　　　　　　　　　　　　　
  Maki Kawai; Hirofumi Uchimiya
  Annals of Botany, Volume：86, Number：2, First page：405, Last page：414, 2000
  We investigated the cellular events associated with cell death in the coleoptile of rice plants (Oryza sativa L.). Seeds germinated under submergence produced coleoptiles that were more elongated than those grown under aerobic conditions. Transfer of seedlings to aerobic conditions was associated with coleoptile opening (i.e. splitting) due to death of specific cells in the side of the organ. Another type of cell death occurred in the formation of lysigenous aerenchyma. Senescence of the coleoptile was also noted, during which discolouration of the chlorophyll and tissue browning were apparent. DNA fragmentation was observed by deoxynucleotidyltransferase-mediated dUTP nick end labelling (TUNEL) assay, and further confirmed by the appearance of oligonucleosomal DNA ladders in senescent coleoptile cells. Two nucleases (Nuc-a and Nuc-b) were detected by in-gel-assay from proteins isolated from coleoptiles. Nuc-a, commonly observed in three cell death phases required either Ca2+ or Mg2+, whereas Nuc-b which appeared during senescence required both Ca2+ and Mg2+. Both nucleases were strongly inhibited by Zn2+. (C) 2000 Annals of Botany Company.
  Academic Press, English
  DOI：https://doi.org/10.1006/anbo.2000.1199
  DOI ID：10.1006/anbo.2000.1199, ISSN：0305-7364, SCOPUS ID：0033832231
• Ion beam as a noble tool to induce apoptosis-like cell death in roots of maize (Zea mays L.)　　　　　　　　　　　　　　　
  Maki Kawai; Yasuhiko Kobayashi; Aiko Hirata; Yutaka Oono; Hiroshi Watanabe; Hirofumi Uchimiya
  Plant Biotechnology, Volume：17, Number：4, First page：305, Last page：308, 2000
  Maize seedlings were irradiated with 20Ne8+ generated by the AVF cyclotron. The growth suppression at the different dosages of ion beam was observed in both root and coleoptile. DNA laddering was also observed at the dosage over 100 Gy. In addition, abnormal morphological changes including chromatin condensation, typical of apoptosis in animal cells, were noted by light and electron microscopy. Our results indicate that the ion beam can serve as an effective tool to induce apoptosis-like cell death in plant cells.
  DOI：https://doi.org/10.5511/plantbiotechnology.17.305
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=0000853046&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=0000853046&origin=inward
  DOI ID：10.5511/plantbiotechnology.17.305, ISSN：1342-4580, eISSN：1347-6114, CiNii Articles ID：10010147080, SCOPUS ID：0000853046
• Transverse vein differentiation associated with gas space formation - Fate of the middle cell layer in leaf sheath development of rice　　　　　　　　　　　　　　　
  C Matsukura; M Kawai; K Toyofuku; RA Barrero; H Uchimiya; J Yamaguchi
  ANNALS OF BOTANY, Volume：85, Number：1, First page：19, Last page：27, Jan. 2000
  In monocotyledons, the leaf vascular network consists of a hierarchical sequence of vertical vascular bundles and numerous transverse veins that interconnect adjacent vertical veins. In the leaf sheath of these species, especially grasses, lysigenous gas cavities (gas spaces) are developed into intervascular spaces and provide a gas conducting system to non-aerial Darts under flooded conditions. The spatial relationship between gas space formation and transverse vein differentiation was investigated using the leaf sheath of rice (Oryza sativa L.). Histochemical observation showed that patterns of differentiation of the transverse vein are distinct from those of vertical vascular bundles. On the other hand, gas spaces are formed through the processes of cell death (collapse). Both events are initiated at a specific cell position in the middle layers of the leaf sheath, from which the vascular system of the leaf is derived; this indicates that differentiation of transverse veins is associated with gas space formation. The cell-to-cell movement of fluorescein isothiocyanate-conjugated dextran injected into middle layer cells coincided with the area where cell collapse occurred, indicating a close relationship between the middle and adaxial cell layers, but not abaxial cell layers. A uniform cell number between each transverse vein in the leaf sheath suggested the involvement of spatial regulation in transverse vein formation regardless of clonal history at the later stage of leaf vein canalization. (C) 2000 Annals of Botany Company.
  ACADEMIC PRESS LTD, English
  DOI：https://doi.org/10.1006/anbo.1999.0993
  DOI ID：10.1006/anbo.1999.0993, ISSN：0305-7364, Web of Science ID：WOS:000084991000004
• Evolutionally conserved plant homologue of the Bax Inhibitor-1 (BI-1) gene capable of suppressing Bax-induced cell death in yeast　　　　　　　　　　　　　　　
  M Kawai; L Pan; JC Reed; H Uchimiya
  FEBS LETTERS, Volume：464, Number：3, First page：143, Last page：147, Dec. 1999
  The plant homologue of Bax Inhibitor-1, a gene described to suppress the cell death induced by Bax gene expression in yeast, was isolated from Oryza sativa L. (rice) and Arabidopsis. The amino acid sequence of the predicted protein was well conserved in both animal and plant (45% in amino acids) and contained six or seven membrane-spanning segments. Northern blot analysis showed that OsBI-1 transcripts were present in all tissues examined. The OsBI-1 cDNA suppressed cell death induced by mammalian Bax in yeast, suggesting functional conservation of this BI-I homologue in the plant kingdom. (C) 1999 Federation of European Biochemical Societies.
  ELSEVIER SCIENCE BV, English
  DOI：https://doi.org/10.1016/S0014-5793(99)01695-6
  DOI ID：10.1016/S0014-5793(99)01695-6, ISSN：0014-5793, CiNii Articles ID：80011426952, PubMed ID：10618494, Web of Science ID：WOS:000084654800009
• TRANSVERSE VEIN DIFFERENTIATION ASSOCIATED WITH THE AIR SPACE FORMATION - CELL FATE OF MIDDLE LAYER IN LEAF SHEATH DEVELOPMENT OF RICE -　　　　　　　　　　　　　　　
  MATSUKURA Chiaki; KAWAI Maki; TOYOFUKU Kyoko; BARRERO Robert A.; UCHIMIYA Hirofumi; YAMAGUCHI Junji
  Volume：40, First page：s15, Last page：s15, Mar. 1999
  English
  ISSN：0032-0781, CiNii Articles ID：10003757764, CiNii Books ID：AA0077511X
• Morphological analysis of apoptosis-like cell death induced by ion beam irradiation in plant cells　　　　　　　　　　　　　　　
  First page：54, Last page：55, 1999
• Cortical cell death, cell proliferation, macromolecular movements and rTip1 expression pattern in roots of rice (Oryza sativa L,) under NaCl stress　　　　　　　　　　　　　　　
  PK Samarajeewa; RA Barrero; C Umeda-Hara; M Kawai; H Uchimiya
  PLANTA, Volume：207, Number：3, First page：354, Last page：361, Jan. 1999
  The mode of action of NaCl in terms of cell proliferation and cell death was examined in seminal roots of rice plants (Oryza sativa L.). Salt/sodium chloride was inhibitory to cell number increase and to cell death in cortical tissue, whereas final cortical cell size was the same as in control roots that were not exposed to NaCl. It seems that NaCl may stimulate the transition phase from cell division to cell elongation. Further analysis of the role of NaCl in the suppression of cortical cell death was confined to a delay in the early stage of cell collapse, which was caused by tonoplast disruption, and plasma-membrane destruction. Sodium chloride did not have any effect on the cell-to-cell movement of macromolecules in the root cortex. In-situ hybridization studies indicated that expression of the gene for tonoplast intrinsic protein (rTip1) was localized predominantly in the epidermal and exodermal cells as well as in metaxylem cells in seminal roots. Upon NaCl treatment, the intensity of rTip1 gene expression was raised in the cortical parenchyma, suggesting that salt plays a role in the rapid onset of cell elongation.
  SPRINGER VERLAG, English
  DOI：https://doi.org/10.1007/s004250050492
  DOI ID：10.1007/s004250050492, ISSN：0032-0935, Web of Science ID：WOS:000078274900004
• Morphological analysis of apoptosis-like cell death induced by ion beam irradiation in plant cells　　　　　　　　　　　　　　　
  JAERI report 1999, First page：54, Last page：55, 1999
• Isolation of a cotton CAP gene: a homologue of adenylyl cyclase-associated protein highly expressed during fiber elongation　　　　　　　　　　　　　　　
  M Kawai; S Aotsuka; H Uchimiya
  PLANT AND CELL PHYSIOLOGY, Volume：39, Number：12, First page：1380, Last page：1383, Dec. 1998
  The cDNA encoding CAP (adenylyl cyclase-associated protein) was isolated from a cotton (Gossypium hirsutum) fiber cDNA library. The cDNA (GhCAP) contained an open reading frame that encoded 471 amino acid residues. RNA blot analysis showed that the cotton CAP gene was expressed mainly in young fibers.
  JAPANESE SOC PLANT PHYSIOLOGISTS, English
  ISSN：0032-0781, Web of Science ID：WOS:000077761600019
• Stimulation of adenylate kinase in rice seedlings under submergence stress　　　　　　　　　　　　　　　
  M Kawai; M Umeda; H Uchimiya
  JOURNAL OF PLANT PHYSIOLOGY, Volume：152, Number：4-5, First page：533, Last page：539, May 1998
  The enzymatic activity of adenylate kinase was stimulated in submerged rice seedlings. This activity was enhanced in every organ of the submerged plants. Treatment with N-2 gas had the same effect as submergence, a result which suggests that O-2-depletion is a major cause of the stimulation of adenylate kinase activity. Northern blot analysis also indicated accumulation of adenylate kinase mRNA under submerged condition. Furthermore, different induction patterns of enzymatic activity were seen in two rice varieties, FR13A and IR42, which are respectively tolerant and intolerant of complete submergence.
  GUSTAV FISCHER VERLAG, English
  ISSN：0176-1617, Web of Science ID：WOS:000073921400029
• Cellular dissection of the degradation pattern of cortical cell death during aerenchyma formation of rice roots　　　　　　　　　　　　　　　
  M Kawai; PK Samarajeewa; RA Barrero; M Nishiguchi; H Uchimiya
  PLANTA, Volume：204, Number：3, First page：277, Last page：287, Mar. 1998
  Cellular events which occur prior to cell collapse were examined in the root cortex of rice (Oryza sativa L.) during aerenchyma formation. Cell collapse started at a specific position in the mid cortex. These cells were distinct in shape from those located towards the periphery. Furthermore, cell collapse was preceded by acidification and the loss of plasma-membrane integrity in cells of the mid cortex. Subsequent death of neighboring cells followed a radial path. Microinjection of molecules of different sizes conjugated with fluorescein isothiocyanate (FITC) showed a molecular exclusion limit of between 9.3 and 19.6 kDa in the root cortex. Furthermore, large molecules, i.e. those around 9.3 kDa, were predominantly transferred in a radial direction, which coincided with the path of sequential cell death.
  SPRINGER VERLAG, English
  DOI：https://doi.org/10.1007/s004250050257
  DOI ID：10.1007/s004250050257, ISSN：0032-0935, CiNii Articles ID：10009945397, Web of Science ID：WOS:000072453800002
• Induction of apoptosis in plant cells by ion beam irradiation　　　　　　　　　　　　　　　
  First page：57, 1998
• Induction of apoptosis in plant cells by ion beam irradiation　　　　　　　　　　　　　　　
  JAERI report 1998, First page：57, 1998
• Genetic engineering for abiotic stress tolerance in plants　　　　　　　　　　　　　　　
  Harcharan S. Dhariwal; Maki Kawai; Hirofumi Uchimiya
  Plant Biotechnology, Volume：15, Number：1, First page：1, Last page：10, 1998
  Development of plant varieties with a high level of tolerance to abiotic stresses is crucial for establishing full yield potential and to stabilize production. Due to the multitude of abiotic stresses and their complex genetic control the progress of breeding for tolerance to abiotic stresses using conventional approaches has not been very rewarding. Recent advances in cellular and molecular biology have made it possible to clone important genes and mobilize them in any organism across barriers of sexual hybridization for stable expression and transmission. All living organisms have evolved mechanisms for avoidance and/or tolerance to one or more of the abiotic stresses. Plants producing crucial enzymes or proteins from various organisms involved in abiotic stress tolerance mechanisms have shown significant advantage over their wild type controls under stressed environment. The enhanced level of compatible osmolytes, radical scavengers and other transgene products correlated with the degree of tolerance. Further understanding of the molecular mechanisms of stress perception, signal transduction and response by plants and other organisms may help to engineer plants with high levels of tolerance to multiple stresses. Perspectives and additional approaches for further improving the tolerance to abiotic stresses through genetic engineering are discussed.
  Japanese Society for Plant Cell and Molecular Biology, English, Book review
  DOI：https://doi.org/10.5511/plantbiotechnology.15.1
  DOI ID：10.5511/plantbiotechnology.15.1, ISSN：1347-6114, CiNii Articles ID：10006290826, SCOPUS ID：54649083917
• ANALYSIS OF AERENCHYMA FORMATION CAUSED BY CELL DEATH IN RICE ROOT　　　　　　　　　　　　　　　
  KAWAI Maki; SAMARAJEEWA P. K.; YAMAGUCHI Masatoshi; UCHIMIYA Hirofumi
  Volume：37, First page：131, Last page：131, Mar. 1996
  English
  ISSN：0032-0781, CiNii Articles ID：10002708306, CiNii Books ID：AA0077511X
• TISSUE-SPECIFIC LOCALIZATION OF ADENYLATE KINASE IN RICE (ORYZA-SATIVA L) PLANTS　　　　　　　　　　　　　　　
  M KAWAI; H UCHIMIYA
  JOURNAL OF PLANT PHYSIOLOGY, Volume：146, Number：3, First page：239, Last page：242, Jun. 1995
  Anti-adenylate kinase (AK) antibody was used to locate AK protein in organs and tissues of rice plants. This antibody reacted with a 27-kDa protein in callus, root, and leaf tissues. Tissue-printing immunoblot analysis revealed that AK proteins were expressed intensively in vascular tissues.
  GUSTAV FISCHER VERLAG, English
  ISSN：0176-1617, Web of Science ID：WOS:A1995RJ37600008
• BIOCHEMICAL-PROPERTIES OF RICE ADENYLATE KINASE AND SUBCELLULAR LOCATION IN PLANT-CELLS　　　　　　　　　　　　　　　
  M KAWAI; H UCHIMIYA
  PLANT MOLECULAR BIOLOGY, Volume：27, Number：5, First page：943, Last page：951, Mar. 1995
  Previously, we characterized nucleotide sequences of two cDNAs encoding adenylate kinase from rice plants (Oryza sativa L.). Each cDNA (Adk-a or Adk-b) was cloned into the expression vector pET 11d-GST to produce GST-AK fusion proteins in Escherichia coli. Recombinant proteins were cleaved by thrombin, and GST-free adenylate kinase proteins were obtained. Enzyme activity profiles of different pH and inhibition effects to the enzyme by Ap5A (adenosine-5'-pentaphospho-5'-adenosine) indicates that both adenylate kinase proteins have similar biochemical characteristics. Among the nucleoside monophosphates (AMP, CMP, GMP and UMP) investigated, only AMP reacted with ATP. Furthermore, using the antiserum against the rice adenylate kinase proteins, the cellular location of adenylate kinase proteins was examined by immunomicroscopic analysis in combination with a subcellular fractionation method. The results indicated that adenylate kinase proteins were distributed largely in cytosol of rice cells.
  KLUWER ACADEMIC PUBL, English
  ISSN：0167-4412, Web of Science ID：WOS:A1995RB39500009
• Sodium Chloride Stimulates Adenylate Kinase Level in Seedlings of Salt-Sensitive Rice Varieties　　　　　　　　　　　　　　　
  Pallepitiya K. Samarajeewa; Maki Kawai; Toyoaki Anai; Atsushi Hirai; Hirofumi Uchimiya
  Journal of Plant Physiology, Volume：147, Number：2, First page：277, Last page：280, 1995
  Comparison of adenylate kinase activities in rice seedlings (Oryza sativa L. cv. Yamahoushi) that had been grown in the absence or presence of NaCl indicated that NaCI apparently stimulated enzyme activities in roots of this salt-sensitive japonica rice cultivar. Such stimulation of enzyme activities is not limited to a specific portion of root tissues. Furthermore, NaCl-induced adenylate kinase activation was confirmed in the indica rice cultivar IR 28 susceptible to salinity-stress, but not in the NaCl-tolerant indica cultivar Nona Bokra. Thus in salt sensitive rice plants, adenylate kinase may play some role in the adenylate homeostatis at the early stages of rice seedling growth subjected to salt-stress. © 1995, Gustav Fischer Verlag, Stuttgart. All rights reserved.
  English
  DOI：https://doi.org/10.1016/S0176-1617(11)81519-1
  DOI ID：10.1016/S0176-1617(11)81519-1, ISSN：0176-1617, SCOPUS ID：0029190285
• Tissus specific localization of adenylate kinase in rice(Oryza sativa L.) plants　　　　　　　　　　　　　　　
  J.Plant Phys., Volume：146, First page：239, Last page：243, 1995
• Molecular characterization of cDNAencoing for adenylate kinase of rice(Oryza sative L.)　　　　　　　　　　　　　　　
  Volume：2, First page：845, Last page：854, 1992
• Molecular characterization of cDNAencoing for adenylate kinase of rice(Oryza sative L.)　　　　　　　　　　　　　　　
  Plant J., Volume：2, First page：845, Last page：854, 1992

• THE MOLECULAR BIOLOGY SOCIETY OF JAPAN
• JAPANESE SOCIETY FOR PLANT CELL AND MOLECULAR BIOLOGY
• THE BOTANICAL SOCIETY OF JAPAN
• THE JAPANESE SOCIETY OF PLANT PHYSIOLOGISTS

• 光合成の多様性を支える電子受容体NADP供給系の変容　　　　　　　　　　　　　　　
  01 Apr. 2024 - 31 Mar. 2026
  Grant amount(Total)：7410000, Direct funding：5700000, Indirect funding：1710000
  Grant number：24H02065
• 植物環境応答におけるNAD(P)(H)代謝ネットワーク制御の分子基盤　　　　　　　　　　　　　　　
  01 Apr. 2022 - 31 Mar. 2026
  Grant amount(Total)：17160000, Direct funding：13200000, Indirect funding：3960000
  Grant number：23K23564
• 植物環境応答におけるNAD(P)(H)代謝ネットワーク制御の分子基盤　　　　　　　　　　　　　　　
  01 Apr. 2022 - 31 Mar. 2026
  Grant amount(Total)：17160000, Direct funding：13200000, Indirect funding：3960000
  Grant number：22H02298
• 酸化還元バランス制御を介した不均一環境への応答機構　　　　　　　　　　　　　　　
  01 Apr. 2023 - 31 Mar. 2025
  Grant amount(Total)：7800000, Direct funding：6000000, Indirect funding：1800000
  Grant number：23H04187
• 植物の不均一環境変動応答を支える細胞内酸化還元力バランス制御　　　　　　　　　　　　　　　
  10 Sep. 2021 - 31 Mar. 2023
  Grant amount(Total)：9360000, Direct funding：7200000, Indirect funding：2160000
  Grant number：21H05647
• 葉緑体機能を支えるレドックス制御システムの包括的解析　　　　　　　　　　　　　　　
  01 Apr. 2019 - 31 Mar. 2023
  Grant amount(Total)：17160000, Direct funding：13200000, Indirect funding：3960000
  Grant number：19H03241
• Research on microdomain visualization probes to elucidate plant immunity　　　　　　　　　　　　　　　
  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Challenging Research (Exploratory), 29 Jun. 2018 - 31 Mar. 2022
  Kawai-Yamada Maki, Saitama University
  Grant amount(Total)：6370000, Direct funding：4900000, Indirect funding：1470000
  In order to examine the functions of microdomains scattered on the plasma membrane, which play an important role in plant disease response, we have developed plant microdomain visualization probes targeting their major constituent lipids. We developed a visualization probe, GFP-D4L, which binds to phytosterols, and succeeded in visualizing microdomain structures on the plasma membrane. We also generated an Arabidopsis line that constitutively expresses GFP-D4L and showed that the microdomain exhibits specific dynamics during disease response.
  Grant number：18K19164
• 植物の環境ストレス応答における生体膜マイクロドメインの構築と機能　　　　　　　　　　　　　　　
  01 Apr. 2018 - 31 Mar. 2022
  Grant amount(Total)：17290000, Direct funding：13300000, Indirect funding：3990000
  Grant number：18H02165
• 葉緑体NADP供給とプロトン駆動力のバランス制御機構の解明　　　　　　　　　　　　　　　
  01 Apr. 2019 - 31 Mar. 2021
  Grant amount(Total)：7540000, Direct funding：5800000, Indirect funding：1740000
  Grant number：19H04715
• プロトン駆動力とNADP量的制御のクロストーク　　　　　　　　　　　　　　　
  01 Apr. 2017 - 31 Mar. 2019
  Grant amount(Total)：8320000, Direct funding：6400000, Indirect funding：1920000
  Grant number：17H05714
• Analysis of plant environmental response through plasmamembrane microdomain　　　　　　　　　　　　　　　
  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), 01 Apr. 2014 - 31 Mar. 2019
  KAWAI-YAMADA Maki, Saitama University
  Grant amount(Total)：17160000, Direct funding：13200000, Indirect funding：3960000
  Plants respond to various environmental stresses through plasmamembrane microdomains. In our previous studied, we demonstrated that the overexpression of Arabidopsis BI-1, which localized on ER membrane, appeared enhanced tolerance to oxidative stress. In this research project, we characterized FAH, ELO, and SLD proteins, which are isolated as interacting factors to BI-1, directly or indirectly. Interestingly, these factors are related to the sphingolipid metabolism. The sphingolipid is known to be involved in the plasmamembrane microdomain. In this study, we produced transgenic plants in which these genes were over-expressing or knock-down. These plants showed modified sphingolipid profiles and different responses to oxidative stresses, suggest that the involvement of sphingolipid metabolism to the plat environmental responses.
  Grant number：26292190
• Analysis of GHG emission dynamics in hydroponics　　　　　　　　　　　　　　　
  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), 2010 - 2012
  YOSHIHARA Toshihiro; HASHIDA Shin-nosuke; GOTO Fumiyuki; SHOJI Kazuhiro; UEMOTO Hiroaki; JOKAN Masafumi; KAWAI Maki, Central Research Institute of Electric Power Industry
  Grant amount(Total)：19370000, Direct funding：14900000, Indirect funding：4470000
  A rockwool based nutrient dripping culture system for tomato was used as a model to clarifychanges in GHG emissions (CO_2, N_2O, and CH_4) from the rhizosphere. The points of the results are as follows: 1. The GHG emissions were highly dependent on the environmental conditions,such as temperature, irradiation, and fertilization. 2. The changes in GHG emission duringthe culture were almost the same between the rockwool culture and a traditional soilculture, although the total GHG emission was basically larger in the soil culture thanin the rockwool culture. 3. Changes in micro floras and the amounts were not correlatedwith the changes in N_2O emission. In particular, we established a continuous and real-timemeasurement system for N_2O emission, and newly discovered a very quick response of theN_2O emission to the fertilization (i.e., The N2O emission began to increase at least within10 to 15 min and peaked around 30 to 60 min from the beginning of each nutrient supply,and backed to the background level at most within 7 h after the end of the supply).
  Grant number：22380139
• 脂肪酸代謝をエフェクターとする植物酸化ストレス応答細胞死の機構　　　　　　　　　　　　　　　
  2009 - 2010
  Grant amount(Total)：6110000, Direct funding：4700000, Indirect funding：1410000
  Grant number：21117505
• -　　　　　　　　　　　　　　　
  Competitive research funding
• -　　　　　　　　　　　　　　　
  Competitive research funding