Performance information

• Induction of systemic resistance through calcium signaling in Arabidopsis exposed to air plasma-generated dinitrogen pentoxide　　　　　　　　　　　　　　　
  Sasaki S.; Iwamoto H.; Takashima K.; Toyota M.; Higashitani A.; Kaneko T.
  PLOS ONE, Volume：20, Number：2, First page：e0318757, Feb. 2025, [Reviewed]
  English
• Calcium signaling triggers early high humidity responses in Arabidopsis thaliana.　　　　　　　　　　　　　　　
  Saad Hussain; Hiraku Suda; Christine H Nguyen; Dawei Yan; Masatsugu Toyota; Keiko Yoshioka; Eiji Nambara
  Proceedings of the National Academy of Sciences of the United States of America, Volume：121, Number：51, First page：e2416270121, Dec. 2024, [Reviewed], ［International magazine］
  Plants need to adapt to fluctuating atmospheric humidity and respond to both high and low humidity. Despite our substantial understanding of plant responses to low humidity, molecular mechanisms underlying the high humidity (HH) response are much less well understood. In this study, we investigated early responses to HH in Arabidopsis. Expression of CYP707A3, encoding an abscisic acid (ABA) 8'-hydroxylase, is induced by HH within 10 min, which leads to a decrease in foliar ABA level. We identified that the combined action of CAMTA3 and CAMTA2 transcription factors regulate this response. This regulation requires a calmodulin (CaM)-binding domain of CAMTA3. Transcriptomes of HH-regulated genes are enriched in those related to calcium signaling, including cyclic nucleotide-gated ion channels (CNGCs). Moreover, HH induces CNGC2- and CNGC4-mediated increases in cytosolic Ca2+ concentrations in leaves within a few minutes. We also found that CNGC2, CNGC4, and CAMTAs participate in HH-induced hyponastic movement of petioles. Taken together, our results indicate that CNGC2/CNGC4-Ca2+-CaM-CAMTA3/CAMTA2 acts as a primary regulatory module to trigger downstream HH responses.
  English, Scientific journal
  DOI：https://doi.org/10.1073/pnas.2416270121
  DOI ID：10.1073/pnas.2416270121, PubMed ID：39661062
• Conservation of Long-Range Signaling in Land Plants via Glutamate Receptor–Like Channels
  Masatsugu Toyota
  Plant And Cell Physiology, Volume：65, Number：4, First page：657, Last page：659, Apr. 2024, [Reviewed]
  Oxford University Press (OUP), Scientific journal
  DOI：https://doi.org/10.1093/pcp/pcae034
  DOI ID：10.1093/pcp/pcae034, ISSN：0032-0781, eISSN：1471-9053
• Cell-free translation system with artificial lipid-monolayer particles as a unique tool for characterizing lipid-monolayer binding proteins.　　　　　　　　　　　　　　　
  Fu Kuroiwa; Hiraku Suda; Maho Yabuki; Kimie Atsuzawa; Haruhiko Yamaguchi; Masatsugu Toyota; Yasuko Kaneko; Satoshi Yamashita; Seiji Takahashi; Yuzuru Tozawa
  Bioscience, biotechnology, and biochemistry, Mar. 2024, [Reviewed], ［International magazine］
  Methods for functional analysis of proteins specifically localizing to lipid monolayers such as rubber particles and lipid droplets are limited. We have succeeded in establishing a system in which artificially prepared lipid monolayer particles are added to a cell-free translation system to confirm the properties of proteins that specifically bind to lipid monolayers in a translation-coupled manner.
  English, Scientific journal
  DOI：https://doi.org/10.1093/bbb/zbae026
  DOI ID：10.1093/bbb/zbae026, PubMed ID：38444196
• Green leaf volatile sensory calcium transduction in Arabidopsis
  Yuri Aratani; Takuya Uemura; Takuma Hagihara; Kenji Matsui; Masatsugu Toyota
  Nature Communications, Volume：14, Number：1, Oct. 2023, [Reviewed]
  Abstract
  
  Plants perceive volatile organic compounds (VOCs) released by mechanically- or herbivore-damaged neighboring plants and induce various defense responses. Such interplant communication protects plants from environmental threats. However, the spatiotemporal dynamics of VOC sensory transduction in plants remain largely unknown. Using a wide-field real-time imaging method, we visualize an increase in cytosolic Ca²⁺ concentration ([Ca²⁺]_cyt) in Arabidopsis leaves following exposure to VOCs emitted by injured plants. We identify two green leaf volatiles (GLVs), (Z)-3-hexenal (Z-3-HAL) and (E)-2-hexenal (E-2-HAL), which increase [Ca²⁺]_cyt in Arabidopsis. These volatiles trigger the expression of biotic and abiotic stress-responsive genes in a Ca²⁺-dependent manner. Tissue-specific high-resolution Ca²⁺ imaging and stomatal mutant analysis reveal that [Ca²⁺]_cyt increases instantly in guard cells and subsequently in mesophyll cells upon Z-3-HAL exposure. These results suggest that GLVs in the atmosphere are rapidly taken up by the inner tissues via stomata, leading to [Ca²⁺]_cyt increases and subsequent defense responses in Arabidopsis leaves.
  Springer Science and Business Media LLC, English, Scientific journal
  DOI：https://doi.org/10.1038/s41467-023-41589-9
  DOI ID：10.1038/s41467-023-41589-9, eISSN：2041-1723
• Cell polarity linked to gravity sensing is generated by LZY translocation from statoliths to the plasma membrane.　　　　　　　　　　　　　　　
  Takeshi Nishimura; Shogo Mori; Hiromasa Shikata; Moritaka Nakamura; Yasuko Hashiguchi; Yoshinori Abe; Takuma Hagihara; Hiroshi Y Yoshikawa; Masatsugu Toyota; Takumi Higaki; Miyo Terao Morita
  Science (New York, N.Y.), Volume：381, Number：6661, First page：1006, Last page：1010, Sep. 2023, [Reviewed], ［International magazine］
  Organisms have evolved under gravitational force, and many sense the direction of gravity by means of statoliths in specialized cells. In flowering plants, starch-accumulating plastids, known as amyloplasts, act as statoliths to facilitate downstream gravitropism. The gravity-sensing mechanism has long been considered a mechanosensing process by which amyloplasts transmit forces to intracellular structures, but the molecular mechanism underlying this has not been elucidated. We show here that LAZY1-LIKE (LZY) family proteins involved in statocyte gravity signaling associate with amyloplasts and the proximal plasma membrane. This results in polar localization according to the direction of gravity. We propose a gravity-sensing mechanism by which LZY translocation to the plasma membrane signals the direction of gravity by transmitting information on the position of amyloplasts.
  English, Scientific journal
  DOI：https://doi.org/10.1126/science.adh9978
  DOI ID：10.1126/science.adh9978, PubMed ID：37561884
• Shoot gravitropism and organ straightening cooperate to arrive at a mechanically favorable shape in Arabidopsis.　　　　　　　　　　　　　　　
  Satoru Tsugawa; Yuzuki Miyake; Keishi Okamoto; Masatsugu Toyota; Hiroki Yagi; Miyo Terao Morita; Ikuko Hara-Nishimura; Taku Demura; Haruko Ueda
  Scientific reports, Volume：13, Number：1, First page：11165, Last page：11165, Jul. 2023, ［International magazine］
  Gravitropism is the plant organ bending in response to gravity, while a straightening mechanism prevents bending beyond the gravitropic set-point angle. The promotion and prevention of bending occur simultaneously around the inflorescence stem tip. How these two opposing forces work together and what part of the stem they affect are unknown. To understand the mechanical forces involved, we rotated wild type and organ-straightening-deficient mutant (myosin xif xik) Arabidopsis plants to a horizontal position to initiate bending. The mutant stems started to bend before the wild-type stems, which led us to hypothesize that the force preventing bending was weaker in mutant. We modeled the wild-type and mutant stems as elastic rods, and evaluated two parameters: an organ-angle-dependent gravitropic-responsive parameter (β) and an organ-curvature-dependent proprioceptive-responsive parameter (γ). Our model showed that these two parameters were lower in mutant than in wild type, implying that, unexpectedly, both promotion and prevention of bending are weak in mutant. Subsequently, finite element method simulations revealed that the compressive stress in the middle of the stem was significantly lower in wild type than in mutant. The results of this study show that myosin-XIk-and-XIf-dependent organ straightening adjusts the stress distribution to achieve a mechanically favorable shape.
  English, Scientific journal
  DOI：https://doi.org/10.1038/s41598-023-38069-x
  DOI ID：10.1038/s41598-023-38069-x, PubMed ID：37460700, PubMed Central ID：PMC10352312
• Local calcium signal transmission in mycelial network exhibits decentralized stress responses.　　　　　　　　　　　　　　　
  Ayaka Itani; Shunsuke Masuo; Riho Yamamoto; Tomoko Serizawa; Yu Fukasawa; Naoki Takaya; Masatsugu Toyota; Shigeyuki Betsuyaku; Norio Takeshita
  PNAS nexus, Volume：2, Number：3, First page：pgad012, Mar. 2023, ［International magazine］
  Many fungi live as mycelia, which are networks of hyphae. Mycelial networks are suited for the widespread distribution of nutrients and water. The logistical capabilities are critical for the extension of fungal survival areas, nutrient cycling in ecosystems, mycorrhizal symbioses, and virulence. In addition, signal transduction in mycelial networks is predicted to be vital for mycelial function and robustness. A lot of cell biological studies have elucidated protein and membrane trafficking and signal transduction in fungal hyphae; however, there are no reports visualizing signal transduction in mycelia. This paper, by using the fluorescent Ca2+ biosensor, visualized for the first time how calcium signaling is conducted inside the mycelial network in response to localized stimuli in the model fungus Aspergillus nidulans. The wavy propagation of the calcium signal inside the mycelium or the signal blinking in the hyphae varies depending on the type of stress and proximity to the stress. The signals, however, only extended around 1,500 μm, suggesting that the mycelium has a localized response. The mycelium showed growth delay only in the stressed areas. Local stress caused arrest and resumption of mycelial growth through reorganization of the actin cytoskeleton and membrane trafficking. To elucidate the downstream of calcium signaling, calmodulin, and calmodulin-dependent protein kinases, the principal intracellular Ca2+ receptors were immunoprecipitated and their downstream targets were identified by mass spectrometry analyses. Our data provide evidence that the mycelial network, which lacks a brain or nervous system, exhibits decentralized response through locally activated calcium signaling in response to local stress.
  English, Scientific journal
  DOI：https://doi.org/10.1093/pnasnexus/pgad012
  DOI ID：10.1093/pnasnexus/pgad012, PubMed ID：36896124, PubMed Central ID：PMC9991499
• Calcium-mediated rapid movements defend against herbivorous insects in Mimosa pudica.　　　　　　　　　　　　　　　
  Takuma Hagihara; Hiroaki Mano; Tomohiro Miura; Mitsuyasu Hasebe; Masatsugu Toyota
  Nature communications, Volume：13, Number：1, First page：6412, Last page：6412, Nov. 2022, [Reviewed], ［International magazine］
  Animals possess specialized systems, e.g., neuromuscular systems, to sense the environment and then move their bodies quickly in response. Mimosa pudica, the sensitive plant, moves its leaves within seconds in response to external stimuli; e.g., touch or wounding. However, neither the plant-wide signaling network that triggers these rapid movements nor the physiological roles of the movements themselves have been determined. Here by simultaneous recording of cytosolic Ca2+ and electrical signals, we show that rapid changes in Ca2+ coupled with action and variation potentials trigger rapid movements in wounded M. pudica. Furthermore, pharmacological manipulation of cytosolic Ca2+ dynamics and CRISPR-Cas9 genome editing technology revealed that an immotile M. pudica is more vulnerable to attacks by herbivorous insects. Our findings provide evidence that rapid movements based on propagating Ca2+ and electrical signals protect this plant from insect attacks.
  English, Scientific journal
  DOI：https://doi.org/10.1038/s41467-022-34106-x
  DOI ID：10.1038/s41467-022-34106-x, PubMed ID：36376294, PubMed Central ID：PMC9663552
• A Continuous Extension of Plant Biotic Interactions Research.　　　　　　　　　　　　　　　
  Yusuke Saijo; Shigeyuki Betsuyaku; Masatsugu Toyota; Kenichi Tsuda
  Plant & cell physiology, Volume：63, Number：10, First page：1321, Last page：1323, Oct. 2022, ［Domestic magazine］
  English, Scientific journal
  DOI：https://doi.org/10.1093/pcp/pcac132
  DOI ID：10.1093/pcp/pcac132, PubMed ID：36135335
• In vivo Imaging Enables Understanding of Seamless Plant Defense Responses to Wounding and Pathogen Attack.　　　　　　　　　　　　　　　
  Masatsugu Toyota; Shigeyuki Betsuyaku
  Plant & cell physiology, Volume：63, Number：10, First page：1391, Last page：1404, Oct. 2022, ［Domestic magazine］
  Plants are exposed to varied biotic stresses, including sequential or simultaneous attack by insects and pathogens. To overcome these complex stresses, plants must perceive each of the stresses, then integrate and relay the information throughout the plant body and eventually activate local and systemic resistance responses. Previous molecular genetic studies identified jasmonic acid and salicylic acid as key plant hormones of wound and immune responses. These hormones, combined with their antagonistic interaction, play critical roles in the initiation and regulation of defense responses against insects and pathogens. Aside from molecular and genetic information, the latest in vivo imaging technology has revealed that plant defense responses are regulated spatially and temporally. In this review, we summarize the current knowledge of local and systemic defense responses against wounding and diseases with a focus on past and recent advances in imaging technologies. We discuss how imaging-based multiparametric analysis has improved our understanding of the spatiotemporal regulation of dynamic plant stress responses. We also emphasize the importance of compiling the knowledge generated from individual studies on plant wounding and immune responses for a more seamless understanding of plant defense responses in the natural environment.
  English, Scientific journal
  DOI：https://doi.org/10.1093/pcp/pcac135
  DOI ID：10.1093/pcp/pcac135, PubMed ID：36165346
• Integration of long-range signals in plants: A model for wound-induced Ca2+, electrical, ROS, and glutamate waves.　　　　　　　　　　　　　　　
  Hiraku Suda; Masatsugu Toyota
  Current opinion in plant biology, Volume：69, First page：102270, Last page：102270, Oct. 2022, ［International magazine］
  Plants show long-range cytosolic Ca2+ signal transduction in response to wounding. Recent advances in in vivo imaging techniques have helped visualize spatiotemporal dynamics of the systemic Ca2+ signals and provided new insights into underlying molecular mechanisms, in which ion channels of the GLUTAMATE RECEPTOR-LIKE (GLR) family are critical for the sensory system. These, along with MECHANOSENSITIVE CHANNEL OF SMALL CONDUCTANCE-LIKE 10 (MSL10) and Arabidopsis H+-ATPase (AHA1) regulate the propagation system. In addition, membrane potential, reactive oxygen species (ROS), and glutamate waves operate in parallel to long-range signal transduction. We summarize these findings and introduce a model that integrates long-range Ca2+, electrical, ROS, and glutamate signals in systemic wound responses.
  English, Scientific journal
  DOI：https://doi.org/10.1016/j.pbi.2022.102270
  DOI ID：10.1016/j.pbi.2022.102270, PubMed ID：35926395
• Mechanosensory trichome cells evoke a mechanical stimuli-induced immune response in Arabidopsis thaliana.　　　　　　　　　　　　　　　
  Mamoru Matsumura; Mika Nomoto; Tomotaka Itaya; Yuri Aratani; Mizuki Iwamoto; Takakazu Matsuura; Yuki Hayashi; Tsuyoshi Mori; Michael J Skelly; Yoshiharu Y Yamamoto; Toshinori Kinoshita; Izumi C Mori; Takamasa Suzuki; Shigeyuki Betsuyaku; Steven H Spoel; Masatsugu Toyota; Yasuomi Tada
  Nature communications, Volume：13, Number：1, First page：1216, Last page：1216, Mar. 2022, ［International magazine］
  Perception of pathogen-derived ligands by corresponding host receptors is a pivotal strategy in eukaryotic innate immunity. In plants, this is complemented by circadian anticipation of infection timing, promoting basal resistance even in the absence of pathogen threat. Here, we report that trichomes, hair-like structures on the epidermis, directly sense external mechanical forces, including raindrops, to anticipate pathogen infections in Arabidopsis thaliana. Exposure of leaf surfaces to mechanical stimuli initiates the concentric propagation of intercellular calcium waves away from trichomes to induce defence-related genes. Propagating calcium waves enable effective immunity against pathogenic microbes through the CALMODULIN-BINDING TRANSCRIPTION ACTIVATOR 3 (CAMTA3) and mitogen-activated protein kinases. We propose an early layer of plant immunity in which trichomes function as mechanosensory cells that detect potential risks.
  English, Scientific journal
  DOI：https://doi.org/10.1038/s41467-022-28813-8
  DOI ID：10.1038/s41467-022-28813-8, PubMed ID：35260555, PubMed Central ID：PMC8904797
• CYCLIC NUCLEOTIDE-GATED ION CHANNEL 2 modulates auxin homeostasis and signaling.　　　　　　　　　　　　　　　
  Sonhita Chakraborty; Masatsugu Toyota; Wolfgang Moeder; Kimberley Chin; Alex Fortuna; Marc Champigny; Steffen Vanneste; Simon Gilroy; Tom Beeckman; Eiji Nambara; Keiko Yoshioka
  Plant physiology, Volume：187, Number：3, First page：1690, Last page：1703, Nov. 2021, ［International magazine］
  Cyclic nucleotide-gated ion channels (CNGCs) have been firmly established as Ca2+-conducting ion channels that regulate a wide variety of physiological responses in plants. CNGC2 has been implicated in plant immunity and Ca2+ signaling due to the autoimmune phenotypes exhibited by null mutants of CNGC2 in Arabidopsis thaliana. However, cngc2 mutants display additional phenotypes that are unique among autoimmune mutants, suggesting that CNGC2 has functions beyond defense and generates distinct Ca2+ signals in response to different triggers. In this study, we found that cngc2 mutants showed reduced gravitropism, consistent with a defect in auxin signaling. This was mirrored in the diminished auxin response detected by the auxin reporters DR5::GUS and DII-VENUS and in a strongly impaired auxin-induced Ca2+ response. Moreover, the cngc2 mutant exhibits higher levels of the endogenous auxin indole-3-acetic acid, indicating that excess auxin in the cngc2 mutant causes its pleiotropic phenotypes. These auxin signaling defects and the autoimmunity syndrome of the cngc2 mutant could be suppressed by loss-of-function mutations in the auxin biosynthesis gene YUCCA6 (YUC6), as determined by identification of the cngc2 suppressor mutant repressor of cngc2 (rdd1) as an allele of YUC6. A loss-of-function mutation in the upstream auxin biosynthesis gene TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS (TAA1, WEAK ETHYLENE INSENSITIVE8) also suppressed the cngc2 phenotypes, further supporting the tight relationship between CNGC2 and the TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS-YUCCA -dependent auxin biosynthesis pathway. Taking these results together, we propose that the Ca2+ signal generated by CNGC2 is a part of the negative feedback regulation of auxin homeostasis in which CNGC2 balances cellular auxin perception by influencing auxin biosynthesis.
  English, Scientific journal
  DOI：https://doi.org/10.1093/plphys/kiab332
  DOI ID：10.1093/plphys/kiab332, PubMed ID：34618044, PubMed Central ID：PMC8566268
• Wide-Field, Real-Time Imaging of Local and Systemic Wound Signals in Arabidopsis.　　　　　　　　　　　　　　　
  Takuya Uemura; Jiaqi Wang; Yuri Aratani; Simon Gilroy; Masatsugu Toyota
  Journal of visualized experiments : JoVE, Number：172, Jun. 2021, ［International magazine］
  Plants respond to mechanical stresses such as wounding and herbivory by inducing defense responses both in the damaged and in the distal undamaged parts. Upon wounding of a leaf, an increase in cytosolic calcium ion concentration (Ca2+ signal) occurs at the wound site. This signal is rapidly transmitted to undamaged leaves, where defense responses are activated. Our recent research revealed that glutamate leaking from the wounded cells of the leaf into the apoplast around them serves as a wound signal. This glutamate activates glutamate receptor-like Ca2+ permeable channels, which then leads to long-distance Ca2+ signal propagation throughout the plant. The spatial and temporal characteristics of these events can be captured with real-time imaging of living plants expressing genetically encoded fluorescent biosensors. Here we introduce a plant-wide, real-time imaging method to monitor the dynamics of both the Ca2+ signals and changes in apoplastic glutamate that occur in response to wounding. This approach uses a wide-field fluorescence microscope and transgenic Arabidopsis plants expressing Green Fluorescent Protein (GFP)-based Ca2+ and glutamate biosensors. In addition, we present methodology to easily elicit wound-induced, glutamate-triggered rapid and long-distance Ca2+ signal propagation. This protocol can also be applied to studies on other plant stresses to help investigate how plant systemic signaling might be involved in their signaling and response networks.
  English, Scientific journal
  DOI：https://doi.org/10.3791/62114
  DOI ID：10.3791/62114, PubMed ID：34152317
• The fast and the furious: rapid long-range signaling in plants.　　　　　　　　　　　　　　　
  Sarah Johns; Takuma Hagihara; Masatsugu Toyota; Simon Gilroy
  Plant physiology, Volume：185, Number：3, First page：694, Last page：706, Apr. 2021, ［International magazine］
  Plants possess a systemic signaling system whereby local stimuli can lead to rapid, plant-wide responses. In addition to the redistribution of chemical messengers that range from RNAs and peptides to hormones and metabolites, a communication system acting through the transmission of electrical, Ca2+, reactive oxygen species and potentially even hydraulic signals has also been discovered. This latter system can propagate signals across many cells each second and researchers are now beginning to uncover the molecular machineries behind this rapid communications network. Thus, elements such as the reactive oxygen species producing NAPDH oxidases and ion channels of the two pore channel, glutamate receptor-like and cyclic nucleotide gated families are all required for the rapid propagation of these signals. Upon arrival at their distant targets, these changes trigger responses ranging from the production of hormones, to changes in the levels of primary metabolites and shifts in patterns of gene expression. These systemic responses occur within seconds to minutes of perception of the initial, local signal, allowing for the rapid deployment of plant-wide responses. For example, an insect starting to chew on just a single leaf triggers preemptive antiherbivore defenses throughout the plant well before it has a chance to move on to the next leaf on its menu.
  English, Scientific journal
  DOI：https://doi.org/10.1093/plphys/kiaa098
  DOI ID：10.1093/plphys/kiaa098, PubMed ID：33793939, PubMed Central ID：PMC8133610
• Gravity sensing in plant and animal cells.　　　　　　　　　　　　　　　
  Ken Takahashi; Hideyuki Takahashi; Takuya Furuichi; Masatsugu Toyota; Makoto Furutani-Seiki; Takeshi Kobayashi; Haruko Watanabe-Takano; Masahiro Shinohara; Takuro Numaga-Tomita; Asako Sakaue-Sawano; Atsushi Miyawaki; Keiji Naruse
  NPJ microgravity, Volume：7, Number：1, First page：2, Last page：2, Feb. 2021, ［International magazine］
  Gravity determines shape of body tissue and affects the functions of life, both in plants and animals. The cellular response to gravity is an active process of mechanotransduction. Although plants and animals share some common mechanisms of gravity sensing in spite of their distant phylogenetic origin, each species has its own mechanism to sense and respond to gravity. In this review, we discuss current understanding regarding the mechanisms of cellular gravity sensing in plants and animals. Understanding gravisensing also contributes to life on Earth, e.g., understanding osteoporosis and muscle atrophy. Furthermore, in the current age of Mars exploration, understanding cellular responses to gravity will form the foundation of living in space.
  English, Scientific journal
  DOI：https://doi.org/10.1038/s41526-020-00130-8
  DOI ID：10.1038/s41526-020-00130-8, PubMed ID：33558517, PubMed Central ID：PMC7870899
• Micromanipulation of amyloplasts with optical tweezers in Arabidopsis stems.　　　　　　　　　　　　　　　
  Yoshinori Abe; Keisuke Meguriya; Takahisa Matsuzaki; Teruki Sugiyama; Hiroshi Y Yoshikawa; Miyo Terao Morita; Masatsugu Toyota
  Plant biotechnology (Tokyo, Japan), Volume：37, Number：4, First page：405, Last page：415, Dec. 2020, ［Domestic magazine］
  Intracellular sedimentation of highly dense, starch-filled amyloplasts toward the gravity vector is likely a key initial step for gravity sensing in plants. However, recent live-cell imaging technology revealed that most amyloplasts continuously exhibit dynamic, saltatory movements in the endodermal cells of Arabidopsis stems. These complicated movements led to questions about what type of amyloplast movement triggers gravity sensing. Here we show that a confocal microscope equipped with optical tweezers can be a powerful tool to trap and manipulate amyloplasts noninvasively, while simultaneously observing cellular responses such as vacuolar dynamics in living cells. A near-infrared (λ=1064 nm) laser that was focused into the endodermal cells at 1 mW of laser power attracted and captured amyloplasts at the laser focus. The optical force exerted on the amyloplasts was theoretically estimated to be up to 1 pN. Interestingly, endosomes and trans-Golgi network were trapped at 30 mW but not at 1 mW, which is probably due to lower refractive indices of these organelles than that of the amyloplasts. Because amyloplasts are in close proximity to vacuolar membranes in endodermal cells, their physical interaction could be visualized in real time. The vacuolar membranes drastically stretched and deformed in response to the manipulated movements of amyloplasts by optical tweezers. Our new method provides deep insights into the biophysical properties of plant organelles in vivo and opens a new avenue for studying gravity-sensing mechanisms in plants.
  English, Scientific journal
  DOI：https://doi.org/10.5511/plantbiotechnology.20.1201a
  DOI ID：10.5511/plantbiotechnology.20.1201a, PubMed ID：33850427, PubMed Central ID：PMC8034693
• Calcium dynamics during trap closure visualized in transgenic Venus flytrap.　　　　　　　　　　　　　　　
  Hiraku Suda; Hiroaki Mano; Masatsugu Toyota; Kenji Fukushima; Tetsuro Mimura; Izuo Tsutsui; Rainer Hedrich; Yosuke Tamada; Mitsuyasu Hasebe
  Nature plants, Volume：6, Number：10, First page：1219, Last page：1224, Oct. 2020, ［International magazine］
  The leaves of the carnivorous plant Venus flytrap, Dionaea muscipula (Dionaea) close rapidly to capture insect prey. The closure response usually requires two successive mechanical stimuli to sensory hairs on the leaf blade within approximately 30 s (refs. 1-4). An unknown biological system in Dionaea is thought to memorize the first stimulus and transduce the signal from the sensory hair to the leaf blade2. Here, we link signal memory to calcium dynamics using transgenic Dionaea expressing a Ca2+ sensor. Stimulation of a sensory hair caused an increase in cytosolic Ca2+ concentration ([Ca2+]cyt) starting in the sensory hair and spreading to the leaf blade. A second stimulus increased [Ca2+]cyt to an even higher level, meeting a threshold that is correlated to the leaf blade closure. Because [Ca2+]cyt gradually decreased after the first stimulus, the [Ca2+]cyt increase induced by the second stimulus was insufficient to meet the putative threshold for movement after about 30 s. The Ca2+ wave triggered by mechanical stimulation moved an order of magnitude faster than that induced by wounding in petioles of Arabidopsis thaliana5 and Dionaea. The capacity for rapid movement has evolved repeatedly in flowering plants. This study opens a path to investigate the role of Ca2+ in plant movement mechanisms and their evolution.
  English, Scientific journal
  DOI：https://doi.org/10.1038/s41477-020-00773-1
  DOI ID：10.1038/s41477-020-00773-1, PubMed ID：33020606
• Tonoplast-localized Ca2+ pumps regulate Ca2+ signals during pattern-triggered immunity in Arabidopsis thaliana.　　　　　　　　　　　　　　　
  Richard Hilleary; Julio Paez-Valencia; Cullen Vens; Masatsugu Toyota; Michael Palmgren; Simon Gilroy
  Proceedings of the National Academy of Sciences of the United States of America, Volume：117, Number：31, First page：18849, Last page：18857, Aug. 2020, ［International magazine］
  One of the major events of early plant immune responses is a rapid influx of Ca2+ into the cytosol following pathogen recognition. Indeed, changes in cytosolic Ca2+ are recognized as ubiquitous elements of cellular signaling networks and are thought to encode stimulus-specific information in their duration, amplitude, and frequency. Despite the wealth of observations showing that the bacterial elicitor peptide flg22 triggers Ca2+ transients, there remain limited data defining the molecular identities of Ca2+ transporters involved in shaping the cellular Ca2+ dynamics during the triggering of the defense response network. However, the autoinhibited Ca2+-ATPase (ACA) pumps that act to expel Ca2+ from the cytosol have been linked to these events, with knockouts in the vacuolar members of this family showing hypersensitive lesion-mimic phenotypes. We have therefore explored how the two tonoplast-localized pumps, ACA4 and ACA11, impact flg22-dependent Ca2+ signaling and related defense responses. The double-knockout aca4/11 exhibited increased basal Ca2+ levels and Ca2+ signals of higher amplitude than wild-type plants. Both the aberrant Ca2+ dynamics and associated defense-related phenotypes could be suppressed by growing the aca4/11 seedlings at elevated temperatures. Relocalization of ACA8 from its normal cellular locale of the plasma membrane to the tonoplast also suppressed the aca4/11 phenotypes but not when a catalytically inactive mutant was used. These observations indicate that regulation of vacuolar Ca2+ sequestration is an integral component of plant immune signaling, but also that the action of tonoplast-localized Ca2+ pumps does not require specific regulatory elements not found in plasma membrane-localized pumps.
  English, Scientific journal
  DOI：https://doi.org/10.1073/pnas.2004183117
  DOI ID：10.1073/pnas.2004183117, PubMed ID：32690691, PubMed Central ID：PMC7414185
• Mechanical Signaling in the Sensitive Plant Mimosa pudica L.　　　　　　　　　　　　　　　
  Takuma Hagihara; Masatsugu Toyota
  Plants (Basel, Switzerland), Volume：9, Number：5, May 2020, ［International magazine］
  As sessile organisms, plants do not possess the nerves and muscles that facilitate movement in most animals. However, several plant species can move quickly in response to various stimuli (e.g., touch). One such plant species, Mimosa pudica L., possesses the motor organ pulvinus at the junction of the leaflet-rachilla, rachilla-petiole, and petiole-stem, and upon mechanical stimulation, this organ immediately closes the leaflets and moves the petiole. Previous electrophysiological studies have demonstrated that a long-distance and rapid electrical signal propagates through M. pudica in response to mechanical stimulation. Furthermore, the spatial and temporal patterns of the action potential in the pulvinar motor cells were found to be closely correlated with rapid movements. In this review, we summarize findings from past research and discuss the mechanisms underlying long-distance signal transduction in M. pudica. We also propose a model in which the action potential, followed by water flux (i.e., a loss of turgor pressure) in the pulvinar motor cells is a critical step to enable rapid movement.
  English, Scientific journal
  DOI：https://doi.org/10.3390/plants9050587
  DOI ID：10.3390/plants9050587, PubMed ID：32375332, PubMed Central ID：PMC7284940
• CRK2 and C-terminal Phosphorylation of NADPH Oxidase RBOHD Regulate Reactive Oxygen Species Production in Arabidopsis.　　　　　　　　　　　　　　　
  Sachie Kimura; Kerri Hunter; Lauri Vaahtera; Huy Cuong Tran; Matteo Citterico; Aleksia Vaattovaara; Anne Rokka; Sara Christina Stolze; Anne Harzen; Lena Meißner; Maya Melina Tabea Wilkens; Thorsten Hamann; Masatsugu Toyota; Hirofumi Nakagami; Michael Wrzaczek
  The Plant cell, Volume：32, Number：4, First page：1063, Last page：1080, Apr. 2020, ［International magazine］
  Reactive oxygen species (ROS) are important messengers in eukaryotic organisms, and their production is tightly controlled. Active extracellular ROS production by NADPH oxidases in plants is triggered by receptor-like protein kinase-dependent signaling networks. Here, we show that CYSTEINE-RICH RLK2 (CRK2) kinase activity is required for plant growth and CRK2 exists in a preformed complex with the NADPH oxidase RESPIRATORY BURST OXIDASE HOMOLOG D (RBOHD) in Arabidopsis (Arabidopsis thaliana). Functional CRK2 is required for the full elicitor-induced ROS burst, and consequently the crk2 mutant is impaired in defense against the bacterial pathogen Pseudomonas syringae pv tomato DC3000. Our work demonstrates that CRK2 regulates plant innate immunity. We identified in vitro CRK2-dependent phosphorylation sites in the C-terminal region of RBOHD. Phosphorylation of S703 RBOHD is enhanced upon flg22 treatment, and substitution of S703 with Ala reduced ROS production in Arabidopsis. Phylogenetic analysis suggests that phospho-sites in the C-terminal region of RBOHD are conserved throughout the plant lineage and between animals and plants. We propose that regulation of NADPH oxidase activity by phosphorylation of the C-terminal region might be an ancient mechanism and that CRK2 is an important element in regulating microbe-associated molecular pattern-triggered ROS production.
  English, Scientific journal
  DOI：https://doi.org/10.1105/tpc.19.00525
  DOI ID：10.1105/tpc.19.00525, PubMed ID：32034035, PubMed Central ID：PMC7145479
• CRK2 Enhances Salt Tolerance by Regulating Callose Deposition in Connection with PLDα1.　　　　　　　　　　　　　　　
  Kerri Hunter; Sachie Kimura; Anne Rokka; Huy Cuong Tran; Masatsugu Toyota; Jyrki P Kukkonen; Michael Wrzaczek
  Plant physiology, Volume：180, Number：4, First page：2004, Last page：2021, Aug. 2019, ［International magazine］
  High salinity is an increasingly prevalent source of stress to which plants must adapt. The receptor-like protein kinases, including members of the Cys-rich receptor-like kinase (CRK) subfamily, are a highly expanded family of transmembrane proteins in plants that are largely responsible for communication between cells and the extracellular environment. Various CRKs have been implicated in biotic and abiotic stress responses; however, their functions on a cellular level remain largely uncharacterized. Here we have shown that CRK2 enhances salt tolerance at the germination stage in Arabidopsis (Arabidopsis thaliana) and also modulates root length. We established that functional CRK2 is required for salt-induced callose deposition. In doing so, we revealed a role for callose deposition in response to increased salinity and demonstrated its importance for salt tolerance during germination. Using fluorescently tagged proteins, we observed specific changes in the subcellular localization of CRK2 in response to various stress treatments. Many of CRK2's cellular functions were dependent on phospholipase D activity, as were the subcellular localization changes. Thus, we propose that CRK2 acts downstream of phospholipase D during salt stress, promoting callose deposition and regulating plasmodesmal permeability, and that CRK2 adopts specific stress-dependent subcellular localization patterns that allow it to carry out its functions.
  English, Scientific journal
  DOI：https://doi.org/10.1104/pp.19.00560
  DOI ID：10.1104/pp.19.00560, PubMed ID：31118265, PubMed Central ID：PMC6670071
• Glutamate triggers long-distance, calcium-based plant defense signaling.　　　　　　　　　　　　　　　
  Masatsugu Toyota; Dirk Spencer; Satoe Sawai-Toyota; Wang Jiaqi; Tong Zhang; Abraham J Koo; Gregg A Howe; Simon Gilroy
  Science (New York, N.Y.), Volume：361, Number：6407, First page：1112, Last page：1115, Sep. 2018, ［International magazine］
  Animals require rapid, long-range molecular signaling networks to integrate sensing and response throughout their bodies. The amino acid glutamate acts as an excitatory neurotransmitter in the vertebrate central nervous system, facilitating long-range information exchange via activation of glutamate receptor channels. Similarly, plants sense local signals, such as herbivore attack, and transmit this information throughout the plant body to rapidly activate defense responses in undamaged parts. Here we show that glutamate is a wound signal in plants. Ion channels of the GLUTAMATE RECEPTOR-LIKE family act as sensors that convert this signal into an increase in intracellular calcium ion concentration that propagates to distant organs, where defense responses are then induced.
  English, Scientific journal
  DOI：https://doi.org/10.1126/science.aat7744
  DOI ID：10.1126/science.aat7744, PubMed ID：30213912
• Molecular Mechanisms of Mechanosensing and Mechanotransduction
  Masatsugu Toyota; Takuya Furuichi; Hidetoshi Iida
  Plant Biomechanics, First page：375, Last page：397, Jun. 2018
  Springer International Publishing, In book
  DOI：https://doi.org/10.1007/978-3-319-79099-2_17
  DOI ID：10.1007/978-3-319-79099-2_17
• Control of basal jasmonate signalling and defence through modulation of intracellular cation flux capacity.　　　　　　　　　　　　　　　
  Aurore Lenglet; Dawid Jaślan; Masatsugu Toyota; Matthias Mueller; Thomas Müller; Gerald Schönknecht; Irene Marten; Simon Gilroy; Rainer Hedrich; Edward E Farmer
  The New phytologist, Volume：216, Number：4, First page：1161, Last page：1169, Dec. 2017, ［International magazine］
  Unknown mechanisms tightly regulate the basal activity of the wound-inducible defence mediator jasmonate (JA) in undamaged tissues. However, the Arabidopsis fatty acid oxygenation upregulated2 (fou2) mutant in vacuolar two-pore channel 1 (TPC1D454N ) displays high JA pathway activity in undamaged leaves. This mutant was used to explore mechanisms controlling basal JA pathway regulation. fou2 was re-mutated to generate novel 'ouf' suppressor mutants. Patch-clamping was used to examine TPC1 cation channel characteristics in the ouf suppressor mutants and in fou2. Calcium (Ca2+ ) imaging was used to study the effects fou2 on cytosolic Ca2+ concentrations. Six intragenic ouf suppressors with near wild-type (WT) JA pathway activity were recovered and one mutant, ouf8, affected the channel pore. At low luminal calcium concentrations, ouf8 had little detectable effect on fou2. However, increased vacuolar Ca2+ concentrations caused channel occlusion, selectively blocking K+ fluxes towards the cytoplasm. Cytosolic Ca2+ concentrations in unwounded fou2 were found to be lower than in the unwounded WT, but they increased in a similar manner in both genotypes following wounding. Basal JA pathway activity can be controlled solely by manipulating endomembrane cation flux capacities. We suggest that changes in endomembrane potential affect JA pathway activity.
  English, Scientific journal
  DOI：https://doi.org/10.1111/nph.14754
  DOI ID：10.1111/nph.14754, PubMed ID：28885692
• Real-time In Vivo Recording of Arabidopsis Calcium Signals During Insect Feeding Using a Fluorescent Biosensor.　　　　　　　　　　　　　　　
  Thomas R Vincent; James Canham; Masatsugu Toyota; Marieta Avramova; Sam T Mugford; Simon Gilroy; Anthony J Miller; Saskia Hogenhout; Dale Sanders
  Journal of visualized experiments : JoVE, Number：126, Aug. 2017, ［International magazine］
  Calcium ions are predicted to be key signaling entities during biotic interactions, with calcium signaling forming an established part of the plant defense response to microbial elicitors and to wounding caused by chewing insects, eliciting systemic calcium signals in plants. However, the role of calcium in vivo during biotic stress is still unclear. This protocol describes the use of a genetically-encoded calcium sensor to detect calcium signals in plants during feeding by a hemipteran pest. Hemipterans such as aphids pierce a small number of cells with specialized, elongated sucking mouthparts, making them the ideal tool to study calcium dynamics when a plant is faced with a biotic stress, which is distinct from a wounding response. In addition, fluorescent biosensors are revolutionizing the measurement of signaling molecules in vivo in both animals and plants. Expressing a GFP-based calcium biosensor, GCaMP3, in the model plant Arabidopsis thaliana allows for the real-time imaging of plant calcium dynamics during insect feeding, with a high spatial and temporal resolution. A repeatable and robust assay has been developed using the fluorescence microscopy of detached GCaMP3 leaves, allowing for the continuous measurement of cytosolic calcium dynamics before, during, and after insect feeding. This reveals a highly-localized rapid calcium elevation around the aphid feeding site that occurs within a few minutes. The protocol can be adapted to other biotic stresses, such as additional insect species, while the use of Arabidopsis thaliana allows for the rapid generation of mutants to facilitate the molecular analysis of the phenomenon.
  English, Scientific journal
  DOI：https://doi.org/10.3791/56142
  DOI ID：10.3791/56142, PubMed ID：28829425, PubMed Central ID：PMC5614317
• The Arabidopsis LAZY1 Family Plays a Key Role in Gravity Signaling within Statocytes and in Branch Angle Control of Roots and Shoots.　　　　　　　　　　　　　　　
  Masatoshi Taniguchi; Masahiko Furutani; Takeshi Nishimura; Moritaka Nakamura; Toyohito Fushita; Kohta Iijima; Kenichiro Baba; Hirokazu Tanaka; Masatsugu Toyota; Masao Tasaka; Miyo Terao Morita
  The Plant cell, Volume：29, Number：8, First page：1984, Last page：1999, Aug. 2017, ［International magazine］
  During gravitropism, the directional signal of gravity is perceived by gravity-sensing cells called statocytes, leading to asymmetric distribution of auxin in the responding organs. To identify the genes involved in gravity signaling in statocytes, we performed transcriptome analyses of statocyte-deficient Arabidopsis thaliana mutants and found two candidates from the LAZY1 family, AtLAZY1/LAZY1-LIKE1 (LZY1) and AtDRO3/AtNGR1/LZY2 We showed that LZY1, LZY2, and a paralog AtDRO1/AtNGR2/LZY3 are redundantly involved in gravitropism of the inflorescence stem, hypocotyl, and root. Mutations of LZY genes affected early processes in gravity signal transduction without affecting amyloplast sedimentation. Statocyte-specific expression of LZY genes rescued the mutant phenotype, suggesting that LZY genes mediate gravity signaling in statocytes downstream of amyloplast displacement, leading to the generation of asymmetric auxin distribution in gravity-responding organs. We also found that lzy mutations reversed the growth angle of lateral branches and roots. Moreover, expression of the conserved C-terminal region of LZY proteins also reversed the growth direction of primary roots in the lzy mutant background. In lateral root tips of lzy multiple mutants, asymmetric distribution of PIN3 and auxin response were reversed, suggesting that LZY genes regulate the direction of polar auxin transport in response to gravity through the control of asymmetric PIN3 expression in the root cap columella.
  English, Scientific journal
  DOI：https://doi.org/10.1105/tpc.16.00575
  DOI ID：10.1105/tpc.16.00575, PubMed ID：28765510, PubMed Central ID：PMC5590491
• Using GCaMP3 to Study Ca2+ Signaling in Nicotiana Species.　　　　　　　　　　　　　　　
  Thomas A DeFalco; Masatsugu Toyota; Van Phan; Purva Karia; Wolfgang Moeder; Simon Gilroy; Keiko Yoshioka
  Plant & cell physiology, Volume：58, Number：7, First page：1173, Last page：1184, Jul. 2017, ［Domestic magazine］
  Ca2+ signaling is a central component of plant biology; however, direct analysis of in vivo Ca2+ levels is experimentally challenging. In recent years, the use of genetically encoded Ca2+ indicators has revolutionized the study of plant Ca2+ signaling, although such studies have been largely restricted to the model plant Arabidopsis. We have developed stable transgenic Nicotiana benthamiana and Nicotiana tabacum lines expressing the single-wavelength fluorescent Ca2+ indicator, GCaMP3. Ca2+ levels in these plants can be imaged in situ using fluorescence microscopy, and these plants can be used qualitatively and semi-quantitatively to evaluate Ca2+ signals in response to a broad array of abiotic or biotic stimuli, such as cold shock or pathogen-associated molecular patterns (PAMPs). Furthermore, these tools can be used in conjunction with well-established N. benthamiana techniques such as virus-induced gene silencing (VIGS) or transient heterologous expression to assay the effects of loss or gain of function on Ca2+ signaling, an approach which we validated via silencing or transient expression of the PAMP receptors FLS2 (Flagellin Sensing 2) or EFR (EF-Tu receptor), respectively. Using these techniques, along with chemical inhibitor treatments, we demonstrate how these plants can be used to elucidate the molecular components governing Ca2+ signaling in response to specific stimuli.
  English, Scientific journal
  DOI：https://doi.org/10.1093/pcp/pcx053
  DOI ID：10.1093/pcp/pcx053, PubMed ID：28482045
• Interplay of Plasma Membrane and Vacuolar Ion Channels, Together with BAK1, Elicits Rapid Cytosolic Calcium Elevations in Arabidopsis during Aphid Feeding.　　　　　　　　　　　　　　　
  Thomas R Vincent; Marieta Avramova; James Canham; Peter Higgins; Natasha Bilkey; Sam T Mugford; Marco Pitino; Masatsugu Toyota; Simon Gilroy; Anthony J Miller; Saskia A Hogenhout; Dale Sanders
  The Plant cell, Volume：29, Number：6, First page：1460, Last page：1479, Jun. 2017, ［International magazine］
  A transient rise in cytosolic calcium ion concentration is one of the main signals used by plants in perception of their environment. The role of calcium in the detection of abiotic stress is well documented; however, its role during biotic interactions remains unclear. Here, we use a fluorescent calcium biosensor (GCaMP3) in combination with the green peach aphid (Myzus persicae) as a tool to study Arabidopsis thaliana calcium dynamics in vivo and in real time during a live biotic interaction. We demonstrate rapid and highly localized plant calcium elevations around the feeding sites of M. persicae, and by monitoring aphid feeding behavior electrophysiologically, we demonstrate that these elevations correlate with aphid probing of epidermal and mesophyll cells. Furthermore, we dissect the molecular mechanisms involved, showing that interplay between the plant defense coreceptor BRASSINOSTEROID INSENSITIVE-ASSOCIATED KINASE1 (BAK1), the plasma membrane ion channels GLUTAMATE RECEPTOR-LIKE 3.3 and 3.6 (GLR3.3 and GLR3.6), and the vacuolar ion channel TWO-PORE CHANNEL1 (TPC1) mediate these calcium elevations. Consequently, we identify a link between plant perception of biotic threats by BAK1, cellular calcium entry mediated by GLRs, and intracellular calcium release by TPC1 during a biologically relevant interaction.
  English, Scientific journal
  DOI：https://doi.org/10.1105/tpc.17.00136
  DOI ID：10.1105/tpc.17.00136, PubMed ID：28559475, PubMed Central ID：PMC5502460
• Wortmannin-induced vacuole fusion enhances amyloplast dynamics in Arabidopsis zigzag1 hypocotyls.　　　　　　　　　　　　　　　
  Ashley Ann Alvarez; Sang Won Han; Masatsugu Toyota; Carla Brillada; Jiameng Zheng; Simon Gilroy; Marcela Rojas-Pierce
  Journal of experimental botany, Volume：67, Number：22, First page：6459, Last page：6472, Dec. 2016, ［International magazine］
  Gravitropism in Arabidopsis shoots depends on the sedimentation of amyloplasts in the endodermis, and a complex interplay between the vacuole and F-actin. Gravity response is inhibited in zigzag-1 (zig-1), a mutant allele of VTI11, which encodes a SNARE protein involved in vacuole fusion. zig-1 seedlings have fragmented vacuoles that fuse after treatment with wortmannin, an inhibitor of phosphatidylinositol 3-kinase, and underscore a role of phosphoinositides in vacuole fusion. Using live-cell imaging with a vertical stage microscope, we determined that young endodermal cells below the apical hook that are smaller than 70 μm in length are the graviperceptive cells in dark-grown hypocotyls. This result was confirmed by local wortmannin application to the top of zig-1 hypocotyls, which enhanced shoot gravitropism in zig-1 mutants. Live-cell imaging of zig-1 hypocotyl endodermal cells indicated that amyloplasts are trapped between juxtaposed vacuoles and their movement is severely restricted. Wortmannin-induced fusion of vacuoles in zig-1 seedlings increased the formation of transvacuolar strands, enhanced amyloplast sedimentation and partially suppressed the agravitropic phenotype of zig-1 seedlings. Hypergravity conditions at 10 g were not sufficient to displace amyloplasts in zig-1, suggesting the existence of a physical tether between the vacuole and amyloplasts. Our results overall suggest that vacuole membrane remodeling may be involved in regulating the association of vacuoles and amyloplasts during graviperception.
  English, Scientific journal
  eISSN：1460-2431, PubMed ID：27816929, PubMed Central ID：PMC5181587
• Isolation of New Gravitropic Mutants under Hypergravity Conditions.　　　　　　　　　　　　　　　
  Akiko Mori; Masatsugu Toyota; Masayoshi Shimada; Mika Mekata; Tetsuya Kurata; Masao Tasaka; Miyo T Morita
  Frontiers in plant science, Volume：7, First page：1443, Last page：1443, 2016, ［International magazine］
  Forward genetics is a powerful approach used to link genotypes and phenotypes, and mutant screening/analysis has provided deep insights into many aspects of plant physiology. Gravitropism is a tropistic response in plants, in which hypocotyls and stems sense the direction of gravity and grow upward. Previous studies of gravitropic mutants have suggested that shoot endodermal cells in Arabidopsis stems and hypocotyls are capable of sensing gravity (i.e., statocytes). In the present study, we report a new screening system using hypergravity conditions to isolate enhancers of gravitropism mutants, and we also describe a rapid and efficient genome mapping method, using next-generation sequencing (NGS) and single nucleotide polymorphism (SNP)-based markers. Using the endodermal-amyloplast less 1 (eal1) mutant, which exhibits defective development of endodermal cells and gravitropism, we found that hypergravity (10 g) restored the reduced gravity responsiveness in eal1 hypocotyls and could, therefore, be used to obtain mutants with further reduction in gravitropism in the eal1 background. Using the new screening system, we successfully isolated six ene (enhancer of eal1) mutants that exhibited little or no gravitropism under hypergravity conditions, and using NGS and map-based cloning with SNP markers, we narrowed down the potential causative genes, which revealed a new genetic network for shoot gravitropism in Arabidopsis.
  English, Scientific journal
  ISSN：1664-462X, PubMed ID：27746791, PubMed Central ID：PMC5040707
• Live cell imaging of cytoskeletal and organelle dynamics in gravity-sensing cells in plant gravitropism.　　　　　　　　　　　　　　　
  Moritaka Nakamura; Masatsugu Toyota; Masao Tasaka; Miyo Terao Morita
  Methods in molecular biology (Clifton, N.J.), Volume：1309, First page：57, Last page：69, 2015, ［International magazine］
  Plants sense gravity and change their morphology/growth direction accordingly (gravitropism). The early process of gravitropism, gravity sensing, is supposed to be triggered by sedimentation of starch-filled plastids (amyloplasts) in statocytes such as root columella cells and shoot endodermal cells. For several decades, many scientists have focused on characterizing the role of the amyloplasts and observed their intracellular sedimentation in various plants. Recently, it has been discovered that the complex sedimentary movements of the amyloplasts are created not only by gravity but also by cytoskeletal/organelle dynamics, such as those of actin filaments and the vacuolar membrane. Thus, to understand how plants sense gravity, we need to analyze both amyloplast movements and their regulatory systems in statocytes. We have developed a vertical-stage confocal microscope that allows multicolor fluorescence imaging of amyloplasts, actin filaments and vacuolar membranes in vertically oriented plant tissues. We also developed a centrifuge microscope that allows bright-field imaging of amyloplasts during centrifugation. These microscope systems provide new insights into gravity-sensing mechanisms in Arabidopsis.
  English, Scientific journal
  DOI：https://doi.org/10.1007/978-1-4939-2697-8_6
  DOI ID：10.1007/978-1-4939-2697-8_6, PubMed ID：25981768
• A tidal wave of signals: calcium and ROS at the forefront of rapid systemic signaling.　　　　　　　　　　　　　　　
  Simon Gilroy; Nobuhiro Suzuki; Gad Miller; Won-Gyu Choi; Masatsugu Toyota; Amith R Devireddy; Ron Mittler
  Trends in plant science, Volume：19, Number：10, First page：623, Last page：30, Oct. 2014, ［International magazine］
  Systemic signaling pathways enable multicellular organisms to prepare all of their tissues and cells to an upcoming challenge that may initially only be sensed by a few local cells. They are activated in plants in response to different stimuli including mechanical injury, pathogen infection, and abiotic stresses. Key to the mobilization of systemic signals in higher plants are cell-to-cell communication events that have thus far been mostly unstudied. The recent identification of systemically propagating calcium (Ca(2+)) and reactive oxygen species (ROS) waves in plants has unraveled a new and exciting cell-to-cell communication pathway that, together with electric signals, could provide a working model demonstrating how plant cells transmit long-distance signals via cell-to-cell communication mechanisms. Here, we summarize recent findings on the ROS and Ca(2+) waves and outline a possible model for their integration.
  English, Scientific journal
  DOI：https://doi.org/10.1016/j.tplants.2014.06.013
  DOI ID：10.1016/j.tplants.2014.06.013, PubMed ID：25088679
• Salt stress-induced Ca2+ waves are associated with rapid, long-distance root-to-shoot signaling in plants.　　　　　　　　　　　　　　　
  Won-Gyu Choi; Masatsugu Toyota; Su-Hwa Kim; Richard Hilleary; Simon Gilroy
  Proceedings of the National Academy of Sciences of the United States of America, Volume：111, Number：17, First page：6497, Last page：502, Apr. 2014, ［International magazine］
  Their sessile lifestyle means that plants have to be exquisitely sensitive to their environment, integrating many signals to appropriate developmental and physiological responses. Stimuli ranging from wounding and pathogen attack to the distribution of water and nutrients in the soil are frequently presented in a localized manner but responses are often elicited throughout the plant. Such systemic signaling is thought to operate through the redistribution of a host of chemical regulators including peptides, RNAs, ions, metabolites, and hormones. However, there are hints of a much more rapid communication network that has been proposed to involve signals ranging from action and system potentials to reactive oxygen species. We now show that plants also possess a rapid stress signaling system based on Ca(2+) waves that propagate through the plant at rates of up to ∼ 400 µm/s. In the case of local salt stress to the Arabidopsis thaliana root, Ca(2+) wave propagation is channeled through the cortex and endodermal cell layers and this movement is dependent on the vacuolar ion channel TPC1. We also provide evidence that the Ca(2+) wave/TPC1 system likely elicits systemic molecular responses in target organs and may contribute to whole-plant stress tolerance. These results suggest that, although plants do not have a nervous system, they do possess a sensory network that uses ion fluxes moving through defined cell types to rapidly transmit information between distant sites within the organism.
  English, Scientific journal
  DOI：https://doi.org/10.1073/pnas.1319955111
  DOI ID：10.1073/pnas.1319955111, PubMed ID：24706854, PubMed Central ID：PMC4035928
• Centrifuge microscopy to analyze the sedimentary movements of amyloplasts　　　　　　　　　　　　　　　
  M. Toyota; N. Ikeda; M. Tasaka; M. T. Morita
  Bio-protocol, Volume：4, Number：17, First page：1229, 2014
  English
• Calcium mobilizations in response to changes in the gravity vector in Arabidopsis seedlings: possible cellular mechanisms.　　　　　　　　　　　　　　　
  Hitoshi Tatsumi; Masatsugu Toyota; Takuya Furuichi; Masahiro Sokabe
  Plant signaling & behavior, Volume：9, Number：8, First page：e29099, 2014, ［International magazine］
  Gravity influences the growth direction of higher plants. Changes in the gravity vector (gravistimulation) immediately promote the increase in the cytoplasmic free calcium ion concentration ([Ca(2+)]c) in Arabidopsis (Arabidopsis thaliana) seedlings. When the seedlings are gravistimulated by reorientation at 180°, a transient two peaked (biphasic) [Ca(2+)]c-increase arises in their hypocotyl and petioles. Parabolic flights (PFs) can generate a variety of gravity-stimuli, and enables us to measure gravity-induced [Ca(2+)]c-increases without specimen rotation, which demonstrate that Arabidopsis seedlings possess a rapid gravity-sensing mechanism linearly transducing a wide range of gravitational changes into Ca(2+) signals on a sub-second timescale. Hypergravity by centrifugation (20 g or 300 g) also induces similar transient [Ca(2+)]c-increases. In this review, we propose models for possible cellular processes of the garavi-stimulus-induced [Ca(2+)]c-increase, and evaluate those by examining whether the model fits well with the kinetic parameters derived from the [Ca(2+)]c-increases obtained by applying gravistimulus with different amplitudes and time sequences.
  English, Scientific journal
  DOI：https://doi.org/10.4161/psb.29099
  DOI ID：10.4161/psb.29099, PubMed ID：25763612, PubMed Central ID：PMC4203510
• Amyloplast displacement is necessary for gravisensing in Arabidopsis shoots as revealed by a centrifuge microscope.　　　　　　　　　　　　　　　
  Masatsugu Toyota; Norifumi Ikeda; Satoe Sawai-Toyota; Takehide Kato; Simon Gilroy; Masao Tasaka; Miyo Terao Morita
  The Plant journal : for cell and molecular biology, Volume：76, Number：4, First page：648, Last page：60, Nov. 2013, ［International magazine］
  The starch-statolith hypothesis proposes that starch-filled amyloplasts act as statoliths in plant gravisensing, moving in response to the gravity vector and signaling its direction. However, recent studies suggest that amyloplasts show continuous, complex movements in Arabidopsis shoots, contradicting the idea of a so-called 'static' or 'settled' statolith. Here, we show that amyloplast movement underlies shoot gravisensing by using a custom-designed centrifuge microscope in combination with analysis of gravitropic mutants. The centrifuge microscope revealed that sedimentary movements of amyloplasts under hypergravity conditions are linearly correlated with gravitropic curvature in wild-type stems. We next analyzed the hypergravity response in the shoot gravitropism 2 (sgr2) mutant, which exhibits neither a shoot gravitropic response nor amyloplast sedimentation at 1 g. sgr2 mutants were able to sense and respond to gravity under 30 g conditions, during which the amyloplasts sedimented. These findings are consistent with amyloplast redistribution resulting from gravity-driven movements triggering shoot gravisensing. To further support this idea, we examined two additional gravitropic mutants, phosphoglucomutase (pgm) and sgr9, which show abnormal amyloplast distribution and reduced gravitropism at 1 g. We found that the correlation between hypergravity-induced amyloplast sedimentation and gravitropic curvature of these mutants was identical to that of wild-type plants. These observations suggest that Arabidopsis shoots have a gravisensing mechanism that linearly converts the number of amyloplasts that settle to the 'bottom' of the cell into gravitropic signals. Further, the restoration of the gravitropic response by hypergravity in the gravitropic mutants that we tested indicates that these lines probably have a functional gravisensing mechanism that is not triggered at 1 g.
  English, Scientific journal
  DOI：https://doi.org/10.1111/tpj.12324
  DOI ID：10.1111/tpj.12324, PubMed ID：24004104
• Analyses of a gravistimulation-specific Ca2+ signature in Arabidopsis using parabolic flights.　　　　　　　　　　　　　　　
  Masatsugu Toyota; Takuya Furuichi; Masahiro Sokabe; Hitoshi Tatsumi
  Plant physiology, Volume：163, Number：2, First page：543, Last page：54, Oct. 2013, ［International magazine］
  Gravity is a critical environmental factor affecting the morphology and functions of organisms on the Earth. Plants sense changes in the gravity vector (gravistimulation) and regulate their growth direction accordingly. In Arabidopsis (Arabidopsis thaliana) seedlings, gravistimulation, achieved by rotating the specimens under the ambient 1g of the Earth, is known to induce a biphasic (transient and sustained) increase in cytoplasmic calcium concentration ([Ca(2+)]c). However, the [Ca(2+)]c increase genuinely caused by gravistimulation has not been identified because gravistimulation is generally accompanied by rotation of specimens on the ground (1g), adding an additional mechanical signal to the treatment. Here, we demonstrate a gravistimulation-specific Ca(2+) response in Arabidopsis seedlings by separating rotation from gravistimulation by using the microgravity (less than 10(-4)g) conditions provided by parabolic flights. Gravistimulation without rotating the specimen caused a sustained [Ca(2+)]c increase, which corresponds closely to the second sustained [Ca(2+)]c increase observed in ground experiments. The [Ca(2+)]c increases were analyzed under a variety of gravity intensities (e.g. 0.5g, 1.5g, or 2g) combined with rapid switching between hypergravity and microgravity, demonstrating that Arabidopsis seedlings possess a very rapid gravity-sensing mechanism linearly transducing a wide range of gravitational changes (0.5g-2g) into Ca(2+) signals on a subsecond time scale.
  English, Scientific journal
  DOI：https://doi.org/10.1104/pp.113.223313
  DOI ID：10.1104/pp.113.223313, PubMed ID：23835410, PubMed Central ID：PMC3793036
• Mechanosensitive channels are activated by stress in the actin stress fibres, and could be involved in gravity sensing in plants
  H. Tatsumi; T. Furuichi; M. Nakano; M. Toyota; K. Hayakawa; M. Sokabe; H. Iida
  Plant Biology, Volume：16, Number：s1, First page：18, Last page：22, Sep. 2013
  Abstract
  
  Mechanosensitive (MS) channels are expressed in a variety of cells. The molecular and biophysical mechanism involved in the regulation of MS channel activities is a central interest in basic biology. MS channels are thought to play crucial roles in gravity sensing in plant cells. To date, two mechanisms have been proposed for MS channel activation. One is that tension development in the lipid bilayer directly activates MS channels. The second mechanism proposes that the cytoskeleton is involved in the channel activation, because MS channel activities are modulated by pharmacological treatments that affect the cytoskeleton. We tested whether tension in the cytoskeleton activates MS channels. Mammalian endothelial cells were microinjected with phalloidin‐conjugated beads, which bound to stress fibres, and a traction force to the actin cytoskeleton was applied by dragging the beads with optical tweezers. MS channels were activated when the force was applied, demonstrating that a sub‐pN force to the actin filaments activates a single MS channel. Plants may use a similar molecular mechanism in gravity sensing, since the cytoplasmic Ca²⁺ concentration increase induced by changes in the gravity vector was attenuated by potential MS channel inhibitors, and by actin‐disrupting drugs. These results support the idea that the tension increase in actin filaments by gravity‐dependent sedimentation of amyloplasts activates MS Ca²⁺‐permeable channels, which can be the molecular mechanism of a Ca²⁺ concentration increase through gravistimulation. We review recent progress in the study of tension sensing by actin filaments and MS channels using advanced biophysical methods, and discuss their possible roles in gravisensing.
  Wiley, Scientific journal
  DOI：https://doi.org/10.1111/plb.12095
  DOI ID：10.1111/plb.12095, ISSN：1435-8603, eISSN：1438-8677
• New candidates for mechano‐sensitive channels potentially involved in gravity sensing in Arabidopsis thaliana
  H. Iida; T. Furuichi; M. Nakano; M. Toyota; M. Sokabe; H. Tatsumi
  Plant Biology, Volume：16, Number：s1, First page：39, Last page：42, Jun. 2013
  Abstract
  
  The mechano‐sensitive channels of plants may sense increases in tension induced by mechanical stimuli, such as touch, wind and turgor pressure, and a gravitational stimulus. Recent studies have identified plant homologues of the bacterial mechano‐sensitive channel MscS, which is gated by membrane tension and reduces intracellular osmolality by releasing small osmolytes from bacterial cells. However, the physiological roles of these homologues have not yet been clearly elucidated, and only two of them have been shown to be involved in the protection of osmotically stressed plastids in Arabidopsis thaliana. We identified another group of candidates for mechano‐sensitive channels in Arabidopsis, named MCA1 and MCA2, whose homologues are exclusively found in plant genomes. MCA1 and MCA2 are composed of 421 and 416 amino acid residues, respectively, share 73% homology in their amino acid sequences, and are not homologous to any known ion channels or transporters. Our structural study revealed that the N‐terminal region (one to 173 amino acids) of both proteins was necessary and sufficient for Ca²⁺ influx activity. Interestingly, this region had one putative transmembrane segment containing an Asp residue whose substitution mutation abolished this activity. Our physiological study suggested that MCA1 expressed at the root tip was required for sensing the hardness of the agar medium or soil. In addition, MCA1 and MCA2 were shown to be responsible for hypo‐osmotic shock‐induced increases in [Ca²⁺]_cyt. Thus, both proteins appear to be involved in the process of sensing mechanical stresses. We discussed the possible role of both proteins in sensing mechanical and gravitational stimuli.
  Wiley, Scientific journal
  DOI：https://doi.org/10.1111/plb.12044
  DOI ID：10.1111/plb.12044, ISSN：1435-8603, eISSN：1438-8677
• Ca2+ waves and ROS in long distance root-to-shoot signalling　　　　　　　　　　　　　　　
  W. Choi; M. Toyota; R. Hilleary; S. Swanson; S. Gilroy
  BioTechnologia, Volume：94, Number：2, First page：215, Last page：216, 2013
  English
• Gravitropism and mechanical signaling in plants.　　　　　　　　　　　　　　　
  Masatsugu Toyota; Simon Gilroy
  American journal of botany, Volume：100, Number：1, First page：111, Last page：25, Jan. 2013, ［International magazine］
  Mechanical stress is a critical signal affecting morphogenesis and growth and is caused by a large variety of environmental stimuli such as touch, wind, and gravity in addition to endogenous forces generated by growth. On the basis of studies dating from the early 19th century, the plant mechanical sensors and response components related to gravity can be divided into two types in terms of their temporal character: sensors of the transient stress of reorientation (phasic signaling) and sensors capable of monitoring and responding to the extended, continuous gravitropic signal for the duration of the tropic growth response (tonic signaling). In the case of transient stress, changes in the concentrations of ions in the cytoplasm play a central role in mechanosensing and are likely a key component of initial gravisensing. Potential candidates for mechanosensitive channels have been identified in Arabidopsis thaliana and may provide clues to these rapid, ionic gravisensing mechanisms. Continuous mechanical stress, on the other hand, may be sensed by other mechanisms in addition to the rapidly adapting mechnaosensitive channels of the phasic system. Sustaining such long-term responses may be through a network of biochemical signaling cascades that would therefore need to be maintained for the many hours of the growth response once they are triggered. However, classical physiological analyses and recent simulation studies also suggest involvement of the cytoskeleton in sensing/responding to long-term mechanoresponse independently of the biochemical signaling cascades triggered by initial graviperception events.
  English, Scientific journal
  DOI：https://doi.org/10.3732/ajb.1200408
  DOI ID：10.3732/ajb.1200408, PubMed ID：23281392
• Live-cell imaging of plant gravity sensing by using a vertical-stage confocal microscope and a centrifuge microscope　　　　　　　　　　　　　　　
  M. Toyota; M. T. Morita; N. Ikeda; M. Tasaka
  Plant Morphology, Volume：24, First page：23, Last page：32, 2012
  English
• An Arabidopsis E3 ligase, SHOOT GRAVITROPISM9, modulates the interaction between statoliths and F-actin in gravity sensing.　　　　　　　　　　　　　　　
  Moritaka Nakamura; Masatsugu Toyota; Masao Tasaka; Miyo Terao Morita
  The Plant cell, Volume：23, Number：5, First page：1830, Last page：48, May 2011, ［International magazine］
  Higher plants use the sedimentation of amyloplasts in statocytes as statolith to sense the direction of gravity during gravitropism. In Arabidopsis thaliana inflorescence stem statocyte, amyloplasts are in complex movement; some show jumping-like saltatory movement and some tend to sediment toward the gravity direction. Here, we report that a RING-type E3 ligase SHOOT GRAVITROPISM9 (SGR9) localized to amyloplasts modulates amyloplast dynamics. In the sgr9 mutant, which exhibits reduced gravitropism, amyloplasts did not sediment but exhibited increased saltatory movement. Amyloplasts sometimes formed a cluster that is abnormally entangled with actin filaments (AFs) in sgr9. By contrast, in the fiz1 mutant, an ACT8 semidominant mutant that induces fragmentation of AFs, amyloplasts, lost saltatory movement and sedimented with nearly statically. Both treatment with Latrunculin B, an inhibitor of AF polymerization, and the fiz1 mutation rescued the gravitropic defect of sgr9. In addition, fiz1 decreased saltatory movement and induced amyloplast sedimentation even in sgr9. Our results suggest that amyloplasts are in equilibrium between sedimentation and saltatory movement in wild-type endodermal cells. Furthermore, this equilibrium is the result of the interaction between amyloplasts and AFs modulated by the SGR9. SGR9 may promote detachment of amyloplasts from AFs, allowing the amyloplasts to sediment in the AFs-dependent equilibrium of amyloplast dynamics.
  English, Scientific journal
  DOI：https://doi.org/10.1105/tpc.110.079442
  DOI ID：10.1105/tpc.110.079442, PubMed ID：21602290, PubMed Central ID：PMC3123953
• Developmental changes in crossover frequency in Arabidopsis.　　　　　　　　　　　　　　　
  Masatsugu Toyota; Kentaro Matsuda; Tetsuji Kakutani; Miyo Terao Morita; Masao Tasaka
  The Plant journal : for cell and molecular biology, Volume：65, Number：4, First page：589, Last page：99, Feb. 2011, ［International magazine］
  Parental genomes are generally rearranged by two processes during meiosis: one is the segregation of homologous chromosomes and the other is crossing over between such chromosomes. Although the mechanisms underlying chromosome segregation and crossing over are well understood because of numerous genetic and molecular investigations, their contributions to the rearrangement of genetic information have not yet been analysed at a genome-wide level in Arabidopsis thaliana. We established 343 CAPS or SSLP markers to identify polymorphisms between two different Arabidopsis ecotypes, Col and Ler, which are distributed at an average distance of approximately 400kb between pairs of markers throughout the entire genome. Using these markers, crossover frequencies and chromosome segregation were quantified with respect to sex and age. Our large-scale analysis demonstrated that: (i) crossover frequencies during pollen formation were 1.79 and 1.37 times higher than those during megaspore formation in early and late flowers, respectively (P<0.001); (ii) the crossover frequencies during pollen formation were not significantly different between early and late flowers of main shoots (P>0.05), whereas the frequencies increased 1.30 times with shoot age during megaspore formation (P<0.001); (iii) the effect of aging depended on the developmental age of the individual shoot rather than on the age of the whole plant; and (iv) five chromosomes were randomly selected and mixed during meiosis.
  English, Scientific journal
  DOI：https://doi.org/10.1111/j.1365-313X.2010.04440.x
  DOI ID：10.1111/j.1365-313X.2010.04440.x, PubMed ID：21226880
• Toward understanding the mechanisms of plant gravity (mechano) sensing　　　　　　　　　　　　　　　
  M. Toyota
  JAROS Review of Space Utilization, Volume：22, First page：3-1, Last page：30, 2011
  English
• [Re-examination of starch-statolith hypothesis, a model for gravity sensing mechanism in plants].　　　　　　　　　　　　　　　
  Masatsugu Toyota; Miyo Terao Morita
  Seikagaku. The Journal of Japanese Biochemical Society, Volume：82, Number：8, First page：730, Last page：4, Aug. 2010, ［Domestic magazine］
  Japanese, Scientific journal
  ISSN：0037-1017, PubMed ID：20857687
• The molecular mechanism of the gravi-response in Arabidopsis seedlings　　　　　　　　　　　　　　　
  Hiroshi Tatsumi; Masatsugu Toyota; Takuya Furuichi; Masahiro Sokabe
  Space Utilization Research, Volume：25, First page：4, Last page：5, 2009
  English
• Critical consideration on the relationship between auxin transport and calcium transients in gravity perception of Arabidopsis seedlings.　　　　　　　　　　　　　　　
  Masatsugu Toyota; Takuya Furuichi; Hitoshi Tatsumi; Masahiro Sokabe
  Plant signaling & behavior, Volume：3, Number：8, First page：521, Last page：4, Aug. 2008, ［International magazine］
  Plants regulate their growth and morphogenesis in response to gravity field, known as gravitropism. In the early process of gravitropism, changes in the gravity vector (gravistimulation) are transduced into certain intracellular signals, termed gravity perception. The plant hormone auxin is not only a crucial factor to represent gravitropism but also a potential signaling molecule for gravity perception. Another strong candidate for the signaling molecule is calcium ion of which cytoplasmic concentration ([Ca(2+)](c)) is known to increase in response to gravistimulation. However, relationship between these two factors, say which is in the first place, has been controversial. This issue is addressed here mainly based on recent progress including our latest studies. Gravistimulation by turning plants 180 degrees induced a two-peaked [Ca(2+)](c)-increase lasting for several minutes in Arabidopsis seedlings expressing apoaequorin; only the second peak was sensitive to the gravistimulation. Peak amplitudes of the [Ca(2+)](c)-increase were attenuated by the 10 microM auxin transport inhibitor (TIBA) and vesicle trafficking inhibitor (BFA), whereas the onset time and rate of rise of the second peak were not significantly altered. This result indicates that polar auxin transport is not involved in the initial phase of the second [Ca(2+)](c)-increase. It is likely that the gravi-induced [Ca(2+)](c)-increase constitutes an upstream event of the auxin transport, but may positively be modulated by auxin since its peak amplitude is attenuated by the inhibition of auxin transport.
  English, Scientific journal
  ISSN：1559-2316, PubMed ID：19513245, PubMed Central ID：PMC2634486
• Cytoplasmic calcium increases in response to changes in the gravity vector in hypocotyls and petioles of Arabidopsis seedlings.　　　　　　　　　　　　　　　
  Masatsugu Toyota; Takuya Furuichi; Hitoshi Tatsumi; Masahiro Sokabe
  Plant physiology, Volume：146, Number：2, First page：505, Last page：14, Feb. 2008, ［International magazine］
  Plants respond to a large variety of environmental signals, including changes in the gravity vector (gravistimulation). In Arabidopsis (Arabidopsis thaliana) seedlings, gravistimulation is known to increase the cytoplasmic free calcium concentration ([Ca(2+)](c)). However, organs responsible for the [Ca(2+)](c) increase and the underlying cellular/molecular mechanisms remain to be solved. In this study, using Arabidopsis seedlings expressing apoaequorin, a Ca(2+)-sensitive luminescent protein in combination with an ultrasensitive photon counting camera, we clarified the organs where [Ca(2+)](c) increases in response to gravistimulation and characterized the physiological and pharmacological properties of the [Ca(2+)](c) increase. When the seedlings were gravistimulated by turning 180 degrees, they showed a transient biphasic [Ca(2+)](c) increase in their hypocotyls and petioles. The second peak of the [Ca(2+)](c) increase depended on the angle but not the speed of rotation, whereas the initial peak showed diametrically opposite characters. This suggests that the second [Ca(2+)](c) increase is specific for changes in the gravity vector. The potential mechanosensitive Ca(2+)-permeable channel (MSCC) inhibitors Gd(3+) and La(3+), the Ca(2+) chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA), and the endomembrane Ca(2+)-permeable channel inhibitor ruthenium red suppressed the second [Ca(2+)](c) increase, suggesting that it arises from Ca(2+) influx via putative MSCCs in the plasma membrane and Ca(2+) release from intracellular Ca(2+) stores. Moreover, the second [Ca(2+)](c) increase was attenuated by actin-disrupting drugs cytochalasin B and latrunculin B but not by microtubule-disrupting drugs oryzalin and nocodazole, implying that actin filaments are partially involved in the hypothetical activation of Ca(2+)-permeable channels. These results suggest that the second [Ca(2+)](c) increase via MSCCs is a gravity response in the hypocotyl and petiole of Arabidopsis seedlings.
  English, Scientific journal
  ISSN：0032-0889, PubMed ID：18055589, PubMed Central ID：PMC2245848
• S16B1 Gravity induced Ca ion concentration increases during a parabolic flight in Arabidopsis seedlings(Biophysical Basis of Sensing and Response to the Gravity Field)　　　　　　　　　　　　　　　
  Tatsumi H.; Toyota M.; Furuichi T.; Sokabe M.
  Seibutsu Butsuri, Volume：47, First page：S22, 2007
  The Biophysical Society of Japan General Incorporated Association, English
  DOI：https://doi.org/10.2142/biophys.47.S22_2
  DOI ID：10.2142/biophys.47.S22_2, CiNii Articles ID：110006561204
• Hypergravity stimulation induces changes in intracellular calcium concentration in Arabidopsis seedlings　　　　　　　　　　　　　　　
  Masatsugu Toyota, Takuya Furuichi, Hiroshi Tatsumi, Masahiro Sokabe
  Advances in Space Research, Volume：39, Number：7, First page：1190, Last page：1197, 2007
  Elsevier BV, English, Scientific journal
  DOI：https://doi.org/10.1016/j.asr.2006.12.012
  DOI ID：10.1016/j.asr.2006.12.012, ISSN：0273-1177
• 1P394 Gravity-induced calcium transient devoid of amyloplast contribution may be involved in an early phase of gravitropism in Arabidopsis(15. Cellular signal transduction,Poster Session,Abstract,Meeting Program of EABS & BSJ 2006)　　　　　　　　　　　　　　　
  Toyota Masatsugu; Furuichi Takuya; Tatsumi Hitoshi; Sokabe Masahiro
  Seibutsu Butsuri, Volume：46, Number：2, First page：S245, 2006
  The Biophysical Society of Japan General Incorporated Association, English
  DOI：https://doi.org/10.2142/biophys.46.S245_2
  DOI ID：10.2142/biophys.46.S245_2, CiNii Articles ID：110006193761
• 3P217 Molecular mechanisms of gravity sensing in Arabidopsis seedlings　　　　　　　　　　　　　　　
  Toyota M.; Furuichi T.; Tatsumi H.; Sokabe M.
  Seibutsu Butsuri, Volume：45, First page：S258, 2005
  The Biophysical Society of Japan General Incorporated Association, Japanese
  DOI：https://doi.org/10.2142/biophys.45.S258_1
  DOI ID：10.2142/biophys.45.S258_1, CiNii Articles ID：110004571881

• 揮発性物質を介した植物間コミュニケーションの可視化　　　　　　　　　　　　　　　
  豊田正嗣
  First page：281, Last page：287, Feb. 2025
  Japanese
• 蛍光バイオセンサーによるオジギソウの虫害防御運動シグナルの解明　　　　　　　　　　　　　　　
  豊田正嗣
  Number：58, First page：148, Last page：154, 2023
  Japanese
• 植物の長距離・高速シグナルのリアルタイムイメージング　　　　　　　　　　　　　　　
  上村卓矢; 豊田正嗣
  Volume：100, Number：7, First page：363, Last page：366, 2022
  Japanese, Introduction scientific journal
• 植物のグルタミン酸受容体を介した全身性傷害応答　　　　　　　　　　　　　　　
  豊田正嗣
  Volume：54, Number：6, First page：15, Last page：18, 2022
  Japanese, Introduction scientific journal
• 植物の長距離・高速Ca2+シグナル　　　　　　　　　　　　　　　
  豊田正嗣
  Volume：62, Number：1, First page：56, Last page：57, 2021
  Japanese, Introduction scientific journal
• 植物が傷つけられたことを感じて，全身に情報を伝える仕組み：グルタミン酸の新しい機能　　　　　　　　　　　　　　　
  豊田正嗣
  Volume：58, Number：2, First page：70, Last page：72, 2020
  Japanese, Introduction scientific journal
• 若手研究者の現状 ―アメリカでの苦悩と挑戦―　　　　　　　　　　　　　　　
  豊田正嗣
  Volume：55, Number：1, First page：70, Last page：73, 2020
  Japanese, Introduction scientific journal
• 植物の全身カルシウムイメージング　　　　　　　　　　　　　　　
  豊田正嗣
  Volume：3, Number：2, First page：23, Last page：27, 2019
  Japanese, Introduction scientific journal
• 植物におけるカルシウム／グルタミン酸のリアルタイムイメージング　　　　　　　　　　　　　　　
  豊田正嗣
  Volume：77, Number：2, First page：110, Last page：111, 2019
  Japanese, Introduction scientific journal
• グルタミン酸はカルシウムシグナルを介して植物の全身性傷害防御を引き起こす　　　　　　　　　　　　　　　
  豊田正嗣
  Volume：77, Number：2, First page：134, Last page：135, 2019
  Japanese, Introduction scientific journal
• 植物の全身を流れる高速シグナルを見る　　　　　　　　　　　　　　　
  豊田正嗣
  Volume：902, First page：44, Last page：46, 2019
  Japanese, Introduction scientific journal
• 「かじられた！」とぺんぺん草もシグナルを送る　　　　　　　　　　　　　　　
  豊田正嗣
  Volume：39, First page：42, Last page：43, 2019
  Japanese, Introduction scientific journal
• 植物が傷つけられたことを全身へ伝えるしくみを解明！　　　　　　　　　　　　　　　
  豊田正嗣
  Volume：73, Number：11, First page：73, 2018
  Japanese, Introduction scientific journal
• グルタミン酸とカルシウムシグナルを介した傷害応答　　　　　　　　　　　　　　　
  豊田正嗣
  Volume：53, Number：2, First page：146, Last page：151, 2018
  Japanese, Introduction scientific journal
• 第10章 「重力感知のメカノバイオロジーⅢ：植物細胞」　　　　　　　　　　　　　　　
  豊田正嗣
  Volume：化学同人, First page：125, Last page：139, 2015
  Japanese, Introduction scientific journal
• 重力感受をライブで視るための新しい顕微鏡技術　　　　　　　　　　　　　　　
  豊田正嗣; 森田(寺尾)美代; 池田憲文; 田坂昌生
  Volume：24, First page：23, Last page：32, 2012
  Japanese, Introduction scientific journal
• 第３章 植物の重力(機械)刺激受容機構の解明に向けて　　　　　　　　　　　　　　　
  豊田正嗣
  First page：1, Last page：30, 2011
  Japanese, Introduction scientific journal
• 植物の重力感受機構モデル~デンプン平衡石仮説~の再検証　　　　　　　　　　　　　　　
  豊田正嗣; 森田(寺尾)美代
  Volume：82, Number：8, First page：730, Last page：734, 2010
  Japanese, Introduction scientific journal

• 植物の機械刺激応答を可視化するリアルタイムイメージングの開発　　　　　　　　　　　　　　　
  豊田正嗣
  Feb. 2025, [Invited]
  Japanese
• Cytosolic Calcium Signals : Vital mediators of intra - and inter - plant communication　　　　　　　　　　　　　　　
  Masatsugu Toyota
  2025 KSPB (Korean Society of Plant Biologists) & POSTECH Winter Conference, Feb. 2025, [Invited]
  Feb. 2025 - Feb. 2025, English, Invited oral presentation
• ミステリアスな驚くべき植物の世界　　　　　　　　　　　　　　　
  Jan. 2025, [Invited]
  Japanese, Public discourse
• ついにとらえた！ 植物が触れられたことや傷つけられたことを感じて伝える瞬間　　　　　　　　　　　　　　　
  Jan. 2025, [Invited]
  Japanese, Public discourse
• Mechanosensory cellular and calcium dynamics in plants -tribute to Professor Shingo Takagi-　　　　　　　　　　　　　　　
  豊田正嗣
  Sep. 2024, [Invited]
• Calcium dynamics in intra- and inter-plant communication　　　　　　　　　　　　　　　
  Masatsugu Toyota
  EMBO Workshop Plant Calcium Signaling, Jul. 2024, [Invited]
  English, Invited oral presentation
• 植物の機械刺激受容シグナル伝達機構の研究　　　　　　　　　　　　　　　
  豊田正嗣
  Mar. 2024, [Invited]
  Japanese, Invited oral presentation
• Real-time visualization of intra- and inter-plant communication　　　　　　　　　　　　　　　
  Masatsugu Toyota
  Nov. 2023, [Invited]
  English, Invited oral presentation
• 植物間コミュニケーションを可視化する　　　　　　　　　　　　　　　
  豊田正嗣
  Oct. 2023, [Invited]
  Japanese, Nominated symposium
• Calcium-based rapid defense responses in plants　　　　　　　　　　　　　　　
  Masatsugu Toyota
  International Workshop -Advanced imaging and chemical physiology-, Jun. 2023, [Invited]
  English, Nominated symposium
• Mechanosensory signal transduction in plants　　　　　　　　　　　　　　　
  Masatsugu Toyota
  Plant Cell Dynamics X 2023, May 2023, [Invited]
  English, Invited oral presentation
• オジギソウの運動を引き起こす長距離・高速シグナルを見る　　　　　　　　　　　　　　　
  豊田正嗣
  Mar. 2023, [Invited]
  Mar. 2023 - Mar. 2023, Japanese, Invited oral presentation
• シンプラスト / アポプラストのリソース配分イメージング　　　　　　　　　　　　　　　
  豊田正嗣
  Mar. 2023, [Invited]
  Mar. 2023 - Mar. 2023, Japanese, Invited oral presentation
• カルシウムイメージングで解き明かす植物の驚くべき能力　　　　　　　　　　　　　　　
  豊田正嗣
  Mar. 2023, [Invited]
  Japanese, Invited oral presentation
• オジギソウの機械刺激応答性シグナル伝達　　　　　　　　　　　　　　　
  豊田正嗣
  Dec. 2022, [Invited]
  Nov. 2022 - Dec. 2022, Japanese, Invited oral presentation
• Calcium-based rapid defense movements in Mimosa pudica　　　　　　　　　　　　　　　
  Masatsugu Toyota
  International symposium on "Plant-Structure-Optimization, Nov. 2022, [Invited]
  Nov. 2022 - Nov. 2022, English, Invited oral presentation
• Mechanosensory transduction in the sensitive plant Mimosa pudica　　　　　　　　　　　　　　　
  Masatsugu Toyota
  International symposium on "Plant-Structure-Optimization", Nov. 2022, [Invited]
  English, Nominated symposium
• オジギソウの虫害防御運動を誘発するCa2+/電気シグナル　　　　　　　　　　　　　　　
  豊田正嗣
  Nov. 2022, [Invited]
  Nov. 2022 - Nov. 2022, Japanese
• なぜ・どうやってオジギソウは葉を動かすの？　　　　　　　　　　　　　　　
  豊田正嗣
  Oct. 2022, [Invited]
  Japanese, Public discourse
• 植物の全身を高速伝播する電気化学シグナル　　　　　　　　　　　　　　　
  Sep. 2022, [Invited]
  Sep. 2022 - Sep. 2022, Japanese, Invited oral presentation
• Calcium-based rapid defense movements in Mimosa pudica　　　　　　　　　　　　　　　
  Masatsugu Toyota
  6th International Conference on Plant Vascular Biology(Berlin), Jul. 2022, [Invited]
  Jul. 2022 - Jul. 2022, English, Invited oral presentation
• Calcium-based rapid defense movements in Mimosa pudica　　　　　　　　　　　　　　　
  Masatsugu Toyota
  6th international conference on Plant Vascular Biology, Jul. 2022, [Invited]
  English, Invited oral presentation
• 感じる植物、動く植物　　　　　　　　　　　　　　　
  豊田正嗣
  Mar. 2022, [Invited]
  Japanese
• カルシウムシグナルを介した植物内・植物間情報伝達の可視化　　　　　　　　　　　　　　　
  豊田正嗣
  Mar. 2022, [Invited]
  Japanese, Invited oral presentation
• Dynamic mechanosensory Ca2+ signaling in plants　　　　　　　　　　　　　　　
  豊田正嗣
  Nov. 2021, [Invited]
  Japanese, Public discourse
• 植物の長距離・高速情報伝達を視る　　　　　　　　　　　　　　　
  豊田正嗣
  Nov. 2021, [Invited]
  Japanese, Invited oral presentation
• Mechanosensory transduction in plants　　　　　　　　　　　　　　　
  Masatsugu Toyota
  RIMS Workshop;Mathematical Mechanobiology, Jul. 2021, [Invited]
  English, Nominated symposium
• Plant-wide calcium defense signaling　　　　　　　　　　　　　　　
  Masatsugu Toyota
  THE 31st INTERNATIONAL CONFERENCE ON ARABIDOPSIS RESEARCH (ICAR 2021), Jun. 2021, [Invited]
  English, Invited oral presentation
• 植物のメカノバイオロジー　　　　　　　　　　　　　　　
  豊田正嗣
  Jun. 2021, [Invited]
  Japanese, Nominated symposium
• 植物に神経はあるのか？ - 長距離・高速Ca2+シグナルを介した植物の虫害抵抗性反応 -　　　　　　　　　　　　　　　
  豊田正嗣
  Jan. 2021, [Invited]
  Japanese, Public discourse
• 植物の長距離・高速カルシウムシグナルを可視化する　　　　　　　　　　　　　　　
  豊田正嗣
  Dec. 2020, [Invited]
  Japanese, Invited oral presentation
• 広視野カルシウムイメージングで見る植物の虫害防御応答　　　　　　　　　　　　　　　
  豊田正嗣
  Nov. 2020, [Invited]
  Japanese, Nominated symposium
• 大きな植物をまるごと可視化する ～広視野・高速カルシウムイメージングの挑戦～　　　　　　　　　　　　　　　
  豊田正嗣
  Sep. 2020, [Invited]
  Japanese, Public discourse
• 虫にかじられた植物が発する緊急信号を見る　　　　　　　　　　　　　　　
  豊田正嗣
  Sep. 2020, [Invited]
  Sep. 2020 - Sep. 2020, Japanese, Public discourse
• 海外どうですか？〜欧・米・アジア、比べて見えてくる多様な研究ライフ〜　　　　　　　　　　　　　　　
  豊田正嗣
  Sep. 2020, [Invited]
  Sep. 2020 - Sep. 2020, Japanese, Nominated symposium
• Shining light on rapid signal transduction in plants　　　　　　　　　　　　　　　
  豊田正嗣
  Sep. 2020, [Invited]
  Sep. 2020 - Sep. 2020, Japanese, Invited oral presentation
• Calcium-based intra- and inter-plant communication system　　　　　　　　　　　　　　　
  豊田正嗣
  Mar. 2020, [Invited]
  Japanese, Invited oral presentation
• Strategies of mechanical optimization for plant wound responses　　　　　　　　　　　　　　　
  Masatsugu Toyota
  Strategies of mechanical optimization in plants 2019, Dec. 2019, [Invited]
  English, Nominated symposium
• グルタミン酸受容体を介した植物の長距離カルシウムシグナル　　　　　　　　　　　　　　　
  豊田正嗣
  Nov. 2019, [Invited]
  Japanese, Nominated symposium
• Long-distance, rapid calcium signaling in plant　　　　　　　　　　　　　　　
  Masatsugu Toyota
  Frontiers in plant environmental response research: local signaling, long-distance communication and memory for developmental plasticity 2019, Nov. 2019, [Invited]
  English, Nominated symposium
• Long-range, rapid calcium signaling in plants　　　　　　　　　　　　　　　
  Masatsugu Toyota
  ViPS Seminar (Viikki Plant Science Centre), Nov. 2019, [Invited]
  English, Nominated symposium
• Long-distance Ca2+ transmission via glutamate receptor channels in plants　　　　　　　　　　　　　　　
  豊田正嗣
  Sep. 2019, [Invited]
  Japanese, Invited oral presentation
• Real-time imaging of whole-plant calcium and glutamate dynamics　　　　　　　　　　　　　　　
  Masatsugu Toyota
  The 6th International Symposium on Bioimaging The 28th Annual Meeting of the Bioimaging Society of Japan, Sep. 2019, [Invited]
  English, Invited oral presentation
• グルタミン酸受容体/カルシウムシグナルを介した植物の全身性傷害応答　　　　　　　　　　　　　　　
  豊田正嗣
  Sep. 2019, [Invited]
  Japanese, Invited oral presentation
• Ca2+シグナルを介した植物の全身性傷害応答　　　　　　　　　　　　　　　
  豊田正嗣
  Sep. 2019, [Invited]
  Japanese, Nominated symposium
• Long-distance Ca2+ transmission via glutamate receptor channels in plants　　　　　　　　　　　　　　　
  豊田正嗣
  Sep. 2019, [Invited]
  Japanese, Invited oral presentation
• 植物のメカノバイオロジー -傷害受容を例にして-　　　　　　　　　　　　　　　
  豊田正嗣
  Sep. 2019, [Invited]
  Japanese, Nominated symposium
• Glutamate is a wound signal triggering systemic calcium propagation.　　　　　　　　　　　　　　　
  Masatsugu Toyota
  The 23rd International Conference on Plant Growth Substances, Jun. 2019, [Invited]
  English, Invited oral presentation
• Systemic calcium signaling via glutamate receptor channels in response to mechanical wounding　　　　　　　　　　　　　　　
  Masatsugu Toyota
  IPSR symposium, May 2019, [Invited]
  English, Invited oral presentation
• 高感度バイオセンサーを用いた植物の構造力学的研究　　　　　　　　　　　　　　　
  豊田正嗣
  Mar. 2019, [Invited]
  Japanese, Invited oral presentation
• 植物の機械(重力)刺激受容機構の生物物理学的研究　　　　　　　　　　　　　　　
  豊田正嗣
  Sep. 2018, [Invited]
  Japanese, Invited oral presentation
• Long-range calcium transmission as revealed by whole-plant imaging　　　　　　　　　　　　　　　
  Masatsugu Toyota
  "Frontiers in whole-brain/whole-organ imaging of cellular activities" Saitama University Brain and Body System Science Institute (BBSSI) International Symposium, Nov. 2017, [Invited]
  English, Nominated symposium
• 科学者とは？ ～星の数ほど存在する無限の可能性～　　　　　　　　　　　　　　　
  豊田正嗣
  Sep. 2017, [Invited]
  Japanese, Invited oral presentation
• Systemic calcium waves in plants　　　　　　　　　　　　　　　
  Masatsugu Toyota
  EMBO Workshop -Intercellular communication in development and disease-, Jul. 2017, [Invited]
  English, Nominated symposium
• Molecular mechanisms underlying wound-induced rapid systemic calcium signaling　　　　　　　　　　　　　　　
  M. Toyota, S. Gilroy
  Plant Biology 2016 (American Society of Plant Biologist), Jul. 2016, [Invited]
  English, Invited oral presentation
• Mechanical wounding/insect attack-induced, long-distance, rapid calcium signal transduction in plants 植物の傷害応答性・長距離・高速カルシウムシグナル伝達　　　　　　　　　　　　　　　
  Masatsugu Toyota, S. Gilroy
  Sep. 2015, [Invited]
  English, Invited oral presentation
• Visualization of plant-wide rapid calcium signals underlying systemic resistance responses　　　　　　　　　　　　　　　
  M. Toyota; S. Gilroy
  The 56th Japanese Society of Plant Physiologists Annual Meeting, Mar. 2015, [Invited]
  English, Invited oral presentation
• Mechanical wounding/herbivore attack-induced, long-distance, rapid Ca2+ signal transduction via the phloem　　　　　　　　　　　　　　　
  M. Toyota, S. Gilroy
  The 38th Naito Conference "Molecule-based biological systems", Oct. 2014, [Invited]
  English, Invited oral presentation
• Wound-induced rapid systemic Ca2+ transmission through the phloem　　　　　　　　　　　　　　　
  M. Toyota; S. Gilroy
  Keystone Symposia "Plant Signaling: Dynamic Properties", Feb. 2014
  English, Invited oral presentation
• Wound-induced rapid systemic Ca2+ signaling in Arabidopsis　　　　　　　　　　　　　　　
  M. Toyota; S. Sawai-Toyota; S. Gilroy
  Plant Biology 2013 (American Society of Plant Biologist), Jul. 2013, [Invited]
  English, Invited oral presentation
• A new centrifuge microscope reveals that mobile plastids trigger gravity sensing in Arabidopsis inflorescence stems　　　　　　　　　　　　　　　
  M. Toyota; M. Tasaka; S. Gilroy; M. T. Morita
  The 39th COSPAR Scientific Assembly, Jul. 2012, [Invited]
  English, Invited oral presentation
• A centrifuge microscope reveals that mobile plastids trigger gravity sensing in Arabidopsis shoots　　　　　　　　　　　　　　　
  M. Toyota; M. Tasaka; S. Gilroy; M. T. Morita
  American Society for Gravitational and Space Biology (ASGSB) the 27th Annual Meeting / International Society for Gravitational Physiology (ISGP) the 32nd Annual Meeting, Nov. 2011, [Invited]
  English, Invited oral presentation
• 若い世代が面白いと思える宇宙ライフサイエンス研究　　　　　　　　　　　　　　　
  豊田正嗣
  Sep. 2010, [Invited]
  Japanese, Invited oral presentation
• Analysis of amyloplast dynamics involved in gravity sensing using a novel centrifuge microscope　　　　　　　　　　　　　　　
  M. Toyota; M. Tasaka; M. T. Morita
  The 38th COSPAR Scientific Assembly, Jul. 2010, [Invited]
  English, Invited oral presentation
• 高等植物の重力応答の分子機構　　　　　　　　　　　　　　　
  豊田正嗣; 古市卓也; 辰巳仁史; 曽我部正博
  Dec. 2007, [Invited]
  Japanese, Invited oral presentation
• シロイヌナズナの重力応答性カルシウム上昇　　　　　　　　　　　　　　　
  豊田正嗣; 古市卓也; 辰巳仁史; 曽我部正博
  Sep. 2007, [Invited]
  Japanese, Invited oral presentation
• Pharmacological analysis of calcium transients in response to gravity vector change in Arabidopsis hypocotyls and petioles　　　　　　　　　　　　　　　
  M. Toyota; T. Furuichi; H. Tatsumi; M. Sokabe
  The 36th COSPAR Scientific Assembly 2006, Jul. 2006, [Invited]
  English, Invited oral presentation
• 植物の重力受容を生物物理学的に研究する　　　　　　　　　　　　　　　
  豊田正嗣
  Mar. 2005, [Invited]
  Japanese, Invited oral presentation

• The American Society of Plant Biologists

• 植物感覚プロジェクト　　　　　　　　　　　　　　　
  Oct. 2024 - Mar. 2030
  Principal investigator
• 植物の匂い受容シグナル伝達機構の解明　　　　　　　　　　　　　　　
  Apr. 2024 - Mar. 2028
  Grant amount(Total)：47710000, Direct funding：36700000, Indirect funding：11010000
  Grant number：24H00565
• Studies on the molecular mechanisms and evolution of the generation and transmission of action potential in plants　　　　　　　　　　　　　　　
  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Specially Promoted Research, May 2021 - Mar. 2028
  National Institute for Basic Biology
  Grant amount(Total)：559130000, Direct funding：430100000, Indirect funding：129030000
  Grant number：21H04978
• グルタミン酸受容体を標的としたアミノ酸型バイオスティミュラントの開発　　　　　　　　　　　　　　　
  Apr. 2020 - Mar. 2023
  Masatsugu Toyota, Saitama University, Principal investigator
• Biophysical analysis of the cell wall-plasma membrane interface using GFP-based tension and calcium sensors　　　　　　　　　　　　　　　
  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area), Jun. 2018 - Mar. 2023
  Saitama University
  Grant amount(Total)：55640000, Direct funding：42800000, Indirect funding：12840000
  Grant number：18H05491
• Study of plant gravity sensors using a new microscope　　　　　　　　　　　　　　　
  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Young Scientists (A), Apr. 2017 - Mar. 2020
  Toyota Masatsugu, Saitama University, Principal investigator
  Grant amount(Total)：26260000, Direct funding：20200000, Indirect funding：6060000
  Plants sense the gravity vector and change their growth orientation accordingly, which is known as gravitropism. Based on the Starch-statolith hypothesis, sedimentation of the starch-filled organelle amyloplast in root columella cells or shoot endodermal cells is supposed to trigger gravity sensing in Arabidopsis. The Cholodny-Went model predicts that redistribution (polar transport) of the plant hormone auxin causes differential growth resulting in tropistic responses in roots and shoots. However, little is known about the mechanisms linking the two critical models: Starch-statolith hypothesis and Cholodny-Went model. Using novel imaging techniques (wide-field fluorescent microscope, confocal laser-scanning microscope equipped with optical tweezer and centrifuge fluorescent microscope), we propose a model that gravity-dependent movements of the amyloplasts directly/indirectly facilitate intracellular polar trafficking of the auxin efflux carrier PIN in shoot endodermal cells.
  Grant number：17H05007
• Molecular mechanisms underlying root-to-shoot rapid calcium signaling　　　　　　　　　　　　　　　
  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area), Apr. 2018 - Mar. 2019
  Saitama University
  Grant amount(Total)：10140000, Direct funding：7800000, Indirect funding：2340000
  Grant number：18H04775
• 植物の全身性クロストークを支える長距離・高速カルシウムシグナルの解明と応用　　　　　　　　　　　　　　　
  Apr. 2014 - Mar. 2017
  Masatsugu Toyota, Principal investigator
• 植物のSAチャネルを介した重力感受機構の遺伝学・生物物理学的研究　　　　　　　　　　　　　　　
  2008 - 2010
  Grant amount(Total)：2400000, Direct funding：2400000
  Grant number：08J09762
• 植物の機械刺激受容チャネルによる重力感知機構の生物物理学的研究　　　　　　　　　　　　　　　
  2005 - 2007
  Grant amount(Total)：2700000, Direct funding：2700000
  Grant number：05J07852

• 独自の技術で植物の謎を解明！　　　　　　　　　　　　　　　
  20 Nov. 2024, [Media report]
• 植物の「香り」なぜ放出？情報伝達可視化に成功　　　　　　　　　　　　　　　
  08 Nov. 2024, [Paper]
• 嗅覚や触覚、植物も感じる？ 埼玉大学が仕組み究明へ　　　　　　　　　　　　　　　
  24 Oct. 2024, [Paper]
• 埼玉大の植物研究が「ERATO」に採択 感知・応答の仕組み解明　　　　　　　　　　　　　　　
  17 Oct. 2024, [Paper]
• 日本の基礎研究の危機 このままではもうノーベル賞はとれない!?　　　　　　　　　　　　　　　
  13 Oct. 2024, [Media report]
• 読めば草花を見る目が変わる！植物が持つ脅威の能力。　　　　　　　　　　　　　　　
  29 Sep. 2024, [Paper]
• 植物の匂いコミュニケーション 初めて映像で見た感じている瞬間　　　　　　　　　　　　　　　
  23 Aug. 2024, [Internet]
• 植物の謎　　　　　　　　　　　　　　　
  03 May 2024, [Media report]
• “植物” 支配者は周りを動かす　　　　　　　　　　　　　　　
  11 Dec. 2023, [Media report]
• 埼玉大学・豊田正嗣教授「まれな存在」　　　　　　　　　　　　　　　
  22 Nov. 2023, [Paper]
• 植物間コミュニケーション解明へ　　　　　　　　　　　　　　　
  03 Nov. 2023, [Paper]
• 植物も匂いを「嗅ぐ」 食害の伝達を細胞光らせて可視化　　　　　　　　　　　　　　　
  29 Oct. 2023, [Paper]
• How plants communicate with each other when in danger　　　　　　　　　　　　　　　
  The Washington Post, Climate, 21 Oct. 2023, [Internet]
• 埼玉大学、植物の情報伝達を見える化 「沈黙の警告」発信　　　　　　　　　　　　　　　
  20 Oct. 2023, [Internet]
• Plants Revealed 'Talking' to Each Other About Insects in Video　　　　　　　　　　　　　　　
  Newsweek, Science, 17 Oct. 2023, [Internet]
• How do plants sense stress?　　　　　　　　　　　　　　　
  20 Mar. 2023, [Internet]
• 植物生理学 かじられた葉の防御反応　　　　　　　　　　　　　　　
  17 Mar. 2023, [Paper]
• 世界！オモシロ学者のスゴ動画祭５　　　　　　　　　　　　　　　
  16 Mar. 2023, [Media report]
• オジギソウ “おじぎ”の謎 科学的に解明　　　　　　　　　　　　　　　
  12 Feb. 2023, [Media report]
• 知られざる植物の力　　　　　　　　　　　　　　　
  21 Jan. 2023, [Media report]
• 【世界初】オジギソウ なぜ閉じる？　　　　　　　　　　　　　　　
  01 Jan. 2023, [Media report]
• オジギソウのお辞儀は自衛策、かじられると電気信号で閉鎖…お辞儀なければ食害２倍に　　　　　　　　　　　　　　　
  13 Dec. 2022, [Internet]
• オジギソウ おじぎのなぞを解明　　　　　　　　　　　　　　　
  10 Dec. 2022, [Paper]
• お辞儀で虫から身守る オジギソウ仕組み、埼玉大など研究　　　　　　　　　　　　　　　
  16 Nov. 2022, [Paper]
• オジギソウの葉が動く仕組みを解明　　　　　　　　　　　　　　　
  14 Nov. 2022, [Media report]
• 超・進化論「第１集 植物からのメッセージ」　　　　　　　　　　　　　　　
  06 Nov. 2022, [Media report]
• 「トマト」のトリセツ　　　　　　　　　　　　　　　
  07 Apr. 2022, [Media report]
• 植物の生存戦略とメカニズム　　　　　　　　　　　　　　　
  14 Feb. 2021, [Media report]
• 世界！オモシロ学者のスゴ動画祭　　　　　　　　　　　　　　　
  16 Sep. 2020, [Media report]
• 植物は痛みを感じるのか ― ダメージを全身に伝える仕組みを埼玉大が発見　　　　　　　　　　　　　　　
  24 Sep. 2018
• 植物のカルシウムイオン伝達を可視化　　　　　　　　　　　　　　　
  21 Sep. 2018, [Paper]
• 植物内部の「警報」伝達、可視化に成功　　　　　　　　　　　　　　　
  14 Sep. 2018, [Paper]
• 埼玉大、植物が「身を守る」仕組み解明　　　　　　　　　　　　　　　
  14 Sep. 2018, [Paper]
• Under attack from caterpillars, plants flash a warning signal　　　　　　　　　　　　　　　
  Cosmosmagazine, Nature, 14 Sep. 2018, [Internet]
• Watch a Mutant Plant Burst Into Action When Attacked　　　　　　　　　　　　　　　
  National Geographic, 14 Sep. 2018, [Paper]
• 葉に虫食いで「緊急連絡」、植物の防御機能解明　　　　　　　　　　　　　　　
  14 Sep. 2018, [Paper]
• Blazes of light reveal how plants signal danger long distances　　　　　　　　　　　　　　　
  Science Daily, 13 Sep. 2018, [Internet]
• Blazes Of Light Show Plant's Response To Being Eaten　　　　　　　　　　　　　　　
  Forbs, Science, 13 Sep. 2018, [Paper]
• Watch Plants Light Up When They Get Attacke　　　　　　　　　　　　　　　
  13 Sep. 2018, [Paper]