The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Tatsuya M. Ikeda - One of the best experts on this subject based on the ideXlab platform.
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exogenous methyl Jasmonate alters trichome density on leaf surfaces of rhodes grass chloris gayana kunth
Journal of Plant Growth Regulation, 2010Co-Authors: Hidekazu Kobayashi, Mikiko Yanaka, Tatsuya M. IkedaAbstract:Jasmonates, including jasmonic acid and its derivatives such as methyl Jasmonate (MeJA), are plant growth substances that control various responses. Jasmonates regulate leaf trichome density in dicotyledonous plants, but their effects on the trichome density of monocotyledonous plants, such as those in the Poaceae, remain unclear. In the present study we examined the effects of exogenous MeJA on the trichome density of Rhodes grass, which has three kinds of trichomes: macrohairs, salt glands, and prickles. Exogenous MeJA significantly increased the densities of macrohairs and salt glands on the adaxial and abaxial leaf surfaces and those of prickles on the adaxial leaf surface. Because exogenous MeJA significantly reduced the leaf area, we calculated the number of trichomes per 1000 epidermal cells to eliminate the effects of reduced leaf area. Exogenous MeJA significantly increased the number of macrohairs per 1000 epidermal cells on both adaxial and abaxial leaf surfaces, but it significantly decreased the number of salt glands per 1000 epidermal cells on both surfaces. Exogenous MeJA had no significant effects on the number of prickles per 1000 epidermal cells on either of the leaf surfaces. These results indicate that exogenous MeJA alters the trichome density by affecting leaf area and trichome initiation, and the effects of exogenous MeJA on trichome initiation differ among the various trichome types.
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exogenous methyl Jasmonate alters trichome density on leaf surfaces of rhodes grass chloris gayana kunth
Journal of Plant Growth Regulation, 2010Co-Authors: Hidekazu Kobayashi, Mikiko Yanaka, Tatsuya M. IkedaAbstract:Jasmonates, including jasmonic acid and its derivatives such as methyl Jasmonate (MeJA), are plant growth substances that control various responses. Jasmonates regulate leaf trichome density in dicotyledonous plants, but their effects on the trichome density of monocotyledonous plants, such as those in the Poaceae, remain unclear. In the present study we examined the effects of exogenous MeJA on the trichome density of Rhodes grass, which has three kinds of trichomes: macrohairs, salt glands, and prickles. Exogenous MeJA significantly increased the densities of macrohairs and salt glands on the adaxial and abaxial leaf surfaces and those of prickles on the adaxial leaf surface. Because exogenous MeJA significantly reduced the leaf area, we calculated the number of trichomes per 1000 epidermal cells to eliminate the effects of reduced leaf area. Exogenous MeJA significantly increased the number of macrohairs per 1000 epidermal cells on both adaxial and abaxial leaf surfaces, but it significantly decreased the number of salt glands per 1000 epidermal cells on both surfaces. Exogenous MeJA had no significant effects on the number of prickles per 1000 epidermal cells on either of the leaf surfaces. These results indicate that exogenous MeJA alters the trichome density by affecting leaf area and trichome initiation, and the effects of exogenous MeJA on trichome initiation differ among the various trichome types.
Edward E Farmer - One of the best experts on this subject based on the ideXlab platform.
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glutamate receptor like genes mediate leaf to leaf wound signalling
Nature, 2013Co-Authors: Seyed Ali Reza Mousavi, Adeline Chauvin, Francois Pascaud, Stephan Kellenberger, Edward E FarmerAbstract:Wounded leaves communicate their damage status to one another through a poorly understood process of long-distance signalling. This stimulates the distal production of Jasmonates, potent regulators of defence responses. Using non-invasive electrodes we mapped surface potential changes in Arabidopsis thaliana after wounding leaf eight and found that membrane depolarizations correlated with Jasmonate signalling domains in undamaged leaves. Furthermore, current injection elicited jasmonoyl-isoleucine accumulation, resulting in a transcriptome enriched in RNAs encoding key Jasmonate signalling regulators. From among 34 screened membrane protein mutant lines, mutations in several clade 3 GLUTAMATE RECEPTOR-LIKE genes (GLRs 3.2, 3.3 and 3.6) attenuated wound-induced surface potential changes. Jasmonate-response gene expression in leaves distal to wounds was reduced in a glr3.3 glr3.6 double mutant. This work provides a genetic basis for investigating mechanisms of long-distance wound signalling in plants and indicates that plant genes related to those important for synaptic activity in animals function in organ-to-organ wound signalling. Upon wounding, plants mount a systemic response resulting in the production of Jasmonates, hormones that confer resistance to herbivores; here we identify genes necessary for the electrical activity that leads to Jasmonate synthesis far from the wound itself. Animals respond quickly to wounding via the nervous system. A paper published in Nature in 1992 made the then contentious suggestion that plants too use long-distance electrical signals in response to wounding. It has since become clear that some plants use electrical signalling to control their movements, although the genes underlying this are unknown. Now comes solid experimental and genetic evidence to support the earlier findings on would signalling — and to implicate proteins related to the glutamate receptors that mediate synaptic transmission in vertebrates. Edward Farmer and colleagues demonstrate that wounding an Arabidopsis leaf results in the propagation of electrical activity that stimulates the production of Jasmonates, plant hormones that confer resistance against herbivores and pathogens, at undamaged sites some distance from the wound. The process is mediated by cation channels encoded by the GLR genes.
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velocity estimates for signal propagation leading to systemic jasmonic acid accumulation in wounded arabidopsis
Journal of Biological Chemistry, 2009Co-Authors: Gaetan Glauser, Jeanluc Wolfender, Seyed Ali Reza Mousavi, Lucie Dubugnon, Serge Rudaz, Edward E FarmerAbstract:The wound response prohormone jasmonic acid (JA) accumulates rapidly in tissues both proximal and distal to injury sites in plants. Using quantitative liquid chromatography-mass spectrometry after flash freezing of tissues, we found that JA accumulated within 30 s of injury in wounded Arabidopsis leaves (p = 3.5 e−7). JA augmentation distal to wounds was strongest in unwounded leaves with direct vascular connections to wounded leaves wherein JA levels increased significantly within 120 s of wounding (p = 0.00027). This gave conservative and statistically robust temporal boundaries for the average velocity of the long distance signal leading to distal JA accumulation in unwounded leaves of 3.4–4.5 cm min−1. Like JA, transcripts of the JA synthesis gene LIPOXYGENASE2 (LOX2) and the Jasmonate response gene JAZ10.3 also accumulated to higher levels in directly interconnected leaves than in indirectly connected leaves. JA accumulation in a lox2-1 mutant plant was initiated rapidly after wounding then slowed progressively compared with the wild type (WT). Despite this, JAZ10.3 expression in the two genotypes was similar. Free cyclopentenone Jasmonate levels were similar in both resting WT and lox2-1. In contrast, bound cyclopentenone Jasmonates (arabidopsides) were far lower in lox2-1 than in the WT. The major roles of LOX2 are to generate arabidopsides and the large levels of JA that accumulate proximal to the wound. LOX2 is not essential for some of the most rapid events elicited by wounding.
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spatial and temporal dynamics of Jasmonate synthesis and accumulation in arabidopsis in response to wounding
Journal of Biological Chemistry, 2008Co-Authors: Gaetan Glauser, Edward E Farmer, Elia Grata, Lucie Dubugnon, Serge Rudaz, Jeanluc WolfenderAbstract:Abstract A new metabolite profiling approach combined with an ultrarapid sample preparation procedure was used to study the temporal and spatial dynamics of the wound-induced accumulation of jasmonic acid (JA) and its oxygenated derivatives in Arabidopsis thaliana. In addition to well known Jasmonates, including hydroxyJasmonates (HOJAs), jasmonoyl-isoleucine (JA-Ile), and its 12-hydroxy derivative (12-HOJA-Ile), a new wound-induced dicarboxyJasmonate, 12-carboxyjasmonoyl-l-isoleucine (12-HOOCJA-Ile) was discovered. HOJAs and 12-HOOCJA-Ile were enriched in the midveins of wounded leaves, strongly differentiating them from the other Jasmonate metabolites studied. The polarity of these oxylipins at physiological pH correlated with their appearance in midveins. When the time points of accumulation of different Jasmonates were determined, JA levels were found to increase within 2–5 min of wounding. Remarkably, these changes occurred throughout the plant and were not restricted to wounded leaves. The speed of the stimulus leading to JA accumulation in leaves distal to a wound is at least 3 cm/min. The data give new insights into the spatial and temporal accumulation of Jasmonates and have implications in the understanding of long-distance wound signaling in plants.
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a gain of function allele of tpc1 activates oxylipin biogenesis after leaf wounding in arabidopsis
Plant Journal, 2007Co-Authors: Gustavo Bonaventure, Aurelie Gfeller, William M Proebsting, Stefan Hortensteiner, Aurore Chetelat, Enrico Martinoia, Edward E FarmerAbstract:Summary Jasmonates, potent lipid mediators of defense gene expression in plants, are rapidly synthesized in response to wounding. These lipid mediators also stimulate their own production via a positive feedback circuit, which depends on both JA synthesis and JA signaling. To date, molecular components regulating the activation of Jasmonate biogenesis and its feedback loop have been poorly characterized. We employed a genetic screen capable of detecting the misregulated activity of 13-lipoxygenase, which operates at the entry point of the Jasmonate biosynthesis pathway. Leaf extracts from the Arabidopsis fou2 (fatty acid oxygenation upregulated 2) mutant displayed an increased capacity to catalyze the synthesis of lipoxygenase (LOX) metabolites. Quantitative oxylipin analysis identified less than twofold increased Jasmonate levels in healthy fou2 leaves compared to wild-type; however, wounded fou2 leaves strongly increased Jasmonate biogenesis compared to wounded wild-type. Furthermore, the plants displayed enhanced resistance to the fungus Botrytis cinerea. Higher than wild-type LOX activity and enhanced resistance in the fou2 mutant depend fully on a functional Jasmonate response pathway. The fou2 mutant carries a missense mutation in the putative voltage sensor of the Two Pore Channel 1 gene (TPC1), which encodes a Ca2+-permeant non-selective cation channel. Patch-clamp analysis of fou2 vacuolar membranes showed faster time-dependent conductivity and activation of the mutated channel at lower membrane potentials than wild-type. The results indicate that cation fluxes exert strong control over the positive feedback loop whereby JA stimulates its own synthesis.
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Jasmonates and related oxylipins in plant responses to pathogenesis and herbivory
Current opinion in plant biology, 2003Co-Authors: Edward E Farmer, Emmanuelle Almeras, Venkatesh KrishnamurthyAbstract:The vigorous production of oxygenated fatty acids (oxylipins) is a characteristic response to pathogenesis and herbivory, and is often accompanied by the substantial release of small and reactive lipid-fragmentation products. Some oxylipins, most notably those of the Jasmonate family, have key roles as potent regulators. Recent advances have been made in understanding oxylipin-regulated signal transduction in response to attack. Much Jasmonate signaling takes place via a genetically defined signal network that is linked to the ethylene, auxin, and salicylic acid signal pathways, but a second aspect of Jasmonate signaling is emerging. Some Jasmonates and several newly discovered cyclopentenone lipids can activate or repress gene expression through the activities of a conserved electrophilic atom group.
C Wasternack - One of the best experts on this subject based on the ideXlab platform.
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Jasmonates biosynthesis perception signal transduction and action in plant stress response growth and development an update to the 2007 review in annals of botany
Annals of Botany, 2013Co-Authors: C Wasternack, B HauseAbstract:BACKGROUND: Jasmonates are important regulators in plant responses to biotic and abiotic stresses as well as in development. Synthesized from lipid-constituents, the initially formed jasmonic acid is converted to different metabolites including the conjugate with isoleucine. Important new components of Jasmonate signalling including its receptor were identified, providing deeper insight into the role of Jasmonate signalling pathways in stress responses and development. SCOPE: The present review is an update of the review on Jasmonates published in this journal in 2007. New data of the last five years are described with emphasis on metabolites of Jasmonates, on Jasmonate perception and signalling, on cross-talk to other plant hormones and on Jasmonate signalling in response to herbivores and pathogens, in symbiotic interactions, in flower development, in root growth and in light perception. CONCLUSIONS: The last few years have seen breakthroughs in the identification of Jasmonate ZIM DOMAIN (JAZ) proteins and their interactors such as transcription factors and co-repressors, and the crystallization of the Jasmonate receptor as well as of the enzyme conjugating Jasmonate to amino acids. Now, the complex nature of networks of Jasmonate signalling in stress responses and development including hormone cross-talk can be addressed.
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Jasmonates biosynthesis perception signal transduction and action in plant stress response growth and development an update to the 2007 review in annals of botany
Annals of Botany, 2013Co-Authors: C Wasternack, B HauseAbstract:Background Jasmonates are important regulators in plant responses to biotic and abiotic stresses as well as in development. Synthesized from lipid-constituents, the initially formed jasmonic acid is converted to different metabolites including the conjugate with isoleucine. Important new components of Jasmonate signalling including its receptor were identified, providing deeper insight into the role of Jasmonate signalling pathways in stress responses and development.
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Jasmonates an update on biosynthesis signal transduction and action in plant stress response growth and development
Annals of Botany, 2007Co-Authors: C WasternackAbstract:†Background Jasmonates are ubiquitously occurring lipid-derived compounds with signal functions in plant responses to abiotic and biotic stresses, as well as in plant growth and development. Jasmonic acid and its various metabolites are members of the oxylipin family. Many of them alter gene expression positively or negatively in a regulatory network with synergistic and antagonistic effects in relation to other plant hormones such as salicylate, auxin, ethylene and abscisic acid. †Scope This review summarizes biosynthesis and signal transduction of Jasmonates with emphasis on new findings in relation to enzymes, their crystal structure, new compounds detected in the oxylipin and Jasmonate families, and newly found functions. †Conclusions Crystal structure of enzymes in Jasmonate biosynthesis, increasing number of Jasmonate metabolites and newly identified components of the Jasmonate signal-transduction pathway, including specifically acting transcription factors, have led to new insights into Jasmonate action, but its receptor(s) is/are still missing, in contrast to all other plant hormones.
Hidekazu Kobayashi - One of the best experts on this subject based on the ideXlab platform.
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exogenous methyl Jasmonate alters trichome density on leaf surfaces of rhodes grass chloris gayana kunth
Journal of Plant Growth Regulation, 2010Co-Authors: Hidekazu Kobayashi, Mikiko Yanaka, Tatsuya M. IkedaAbstract:Jasmonates, including jasmonic acid and its derivatives such as methyl Jasmonate (MeJA), are plant growth substances that control various responses. Jasmonates regulate leaf trichome density in dicotyledonous plants, but their effects on the trichome density of monocotyledonous plants, such as those in the Poaceae, remain unclear. In the present study we examined the effects of exogenous MeJA on the trichome density of Rhodes grass, which has three kinds of trichomes: macrohairs, salt glands, and prickles. Exogenous MeJA significantly increased the densities of macrohairs and salt glands on the adaxial and abaxial leaf surfaces and those of prickles on the adaxial leaf surface. Because exogenous MeJA significantly reduced the leaf area, we calculated the number of trichomes per 1000 epidermal cells to eliminate the effects of reduced leaf area. Exogenous MeJA significantly increased the number of macrohairs per 1000 epidermal cells on both adaxial and abaxial leaf surfaces, but it significantly decreased the number of salt glands per 1000 epidermal cells on both surfaces. Exogenous MeJA had no significant effects on the number of prickles per 1000 epidermal cells on either of the leaf surfaces. These results indicate that exogenous MeJA alters the trichome density by affecting leaf area and trichome initiation, and the effects of exogenous MeJA on trichome initiation differ among the various trichome types.
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exogenous methyl Jasmonate alters trichome density on leaf surfaces of rhodes grass chloris gayana kunth
Journal of Plant Growth Regulation, 2010Co-Authors: Hidekazu Kobayashi, Mikiko Yanaka, Tatsuya M. IkedaAbstract:Jasmonates, including jasmonic acid and its derivatives such as methyl Jasmonate (MeJA), are plant growth substances that control various responses. Jasmonates regulate leaf trichome density in dicotyledonous plants, but their effects on the trichome density of monocotyledonous plants, such as those in the Poaceae, remain unclear. In the present study we examined the effects of exogenous MeJA on the trichome density of Rhodes grass, which has three kinds of trichomes: macrohairs, salt glands, and prickles. Exogenous MeJA significantly increased the densities of macrohairs and salt glands on the adaxial and abaxial leaf surfaces and those of prickles on the adaxial leaf surface. Because exogenous MeJA significantly reduced the leaf area, we calculated the number of trichomes per 1000 epidermal cells to eliminate the effects of reduced leaf area. Exogenous MeJA significantly increased the number of macrohairs per 1000 epidermal cells on both adaxial and abaxial leaf surfaces, but it significantly decreased the number of salt glands per 1000 epidermal cells on both surfaces. Exogenous MeJA had no significant effects on the number of prickles per 1000 epidermal cells on either of the leaf surfaces. These results indicate that exogenous MeJA alters the trichome density by affecting leaf area and trichome initiation, and the effects of exogenous MeJA on trichome initiation differ among the various trichome types.
Jeanluc Wolfender - One of the best experts on this subject based on the ideXlab platform.
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axial and radial oxylipin transport
Plant Physiology, 2015Co-Authors: Debora Gasperini, Aurore Chetelat, Adeline Chauvin, Ivan F Acosta, Andrzej Kurenda, Stephanie Stolz, Jeanluc Wolfender, Edward E FarmerAbstract:Jasmonates are oxygenated lipids (oxylipins) that control defense gene expression in response to cell damage in plants. How mobile are these potent mediators within tissues? Exploiting a series of 13-lipoxygenase (13-lox) mutants in Arabidopsis (Arabidopsis thaliana) that displays impaired jasmonic acid (JA) synthesis in specific cell types and using JA-inducible reporters, we mapped the extent of the transport of endogenous Jasmonates across the plant vegetative growth phase. In seedlings, we found that Jasmonate (or JA precursors) could translocate axially from wounded shoots to unwounded roots in a LOX2-dependent manner. Grafting experiments with the wild type and JA-deficient mutants confirmed shoot-to-root oxylipin transport. Next, we used rosettes to investigate radial cell-to-cell transport of Jasmonates. After finding that the LOX6 protein localized to xylem contact cells was not wound inducible, we used the lox234 triple mutant to genetically isolate LOX6 as the only JA precursor-producing LOX in the plant. When a leaf of this mutant was wounded, the JA reporter gene was expressed in distal leaves. Leaf sectioning showed that JA reporter expression extended from contact cells throughout the vascular bundle and into extravascular cells, revealing a radial movement of Jasmonates. Our results add a crucial element to a growing picture of how the distal wound response is regulated in rosettes, showing that both axial (shoot-to-root) and radial (cell-to-cell) transport of oxylipins plays a major role in the wound response. The strategies developed herein provide unique tools with which to identify intercellular Jasmonate transport routes.
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velocity estimates for signal propagation leading to systemic jasmonic acid accumulation in wounded arabidopsis
Journal of Biological Chemistry, 2009Co-Authors: Gaetan Glauser, Jeanluc Wolfender, Seyed Ali Reza Mousavi, Lucie Dubugnon, Serge Rudaz, Edward E FarmerAbstract:The wound response prohormone jasmonic acid (JA) accumulates rapidly in tissues both proximal and distal to injury sites in plants. Using quantitative liquid chromatography-mass spectrometry after flash freezing of tissues, we found that JA accumulated within 30 s of injury in wounded Arabidopsis leaves (p = 3.5 e−7). JA augmentation distal to wounds was strongest in unwounded leaves with direct vascular connections to wounded leaves wherein JA levels increased significantly within 120 s of wounding (p = 0.00027). This gave conservative and statistically robust temporal boundaries for the average velocity of the long distance signal leading to distal JA accumulation in unwounded leaves of 3.4–4.5 cm min−1. Like JA, transcripts of the JA synthesis gene LIPOXYGENASE2 (LOX2) and the Jasmonate response gene JAZ10.3 also accumulated to higher levels in directly interconnected leaves than in indirectly connected leaves. JA accumulation in a lox2-1 mutant plant was initiated rapidly after wounding then slowed progressively compared with the wild type (WT). Despite this, JAZ10.3 expression in the two genotypes was similar. Free cyclopentenone Jasmonate levels were similar in both resting WT and lox2-1. In contrast, bound cyclopentenone Jasmonates (arabidopsides) were far lower in lox2-1 than in the WT. The major roles of LOX2 are to generate arabidopsides and the large levels of JA that accumulate proximal to the wound. LOX2 is not essential for some of the most rapid events elicited by wounding.
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spatial and temporal dynamics of Jasmonate synthesis and accumulation in arabidopsis in response to wounding
Journal of Biological Chemistry, 2008Co-Authors: Gaetan Glauser, Edward E Farmer, Elia Grata, Lucie Dubugnon, Serge Rudaz, Jeanluc WolfenderAbstract:Abstract A new metabolite profiling approach combined with an ultrarapid sample preparation procedure was used to study the temporal and spatial dynamics of the wound-induced accumulation of jasmonic acid (JA) and its oxygenated derivatives in Arabidopsis thaliana. In addition to well known Jasmonates, including hydroxyJasmonates (HOJAs), jasmonoyl-isoleucine (JA-Ile), and its 12-hydroxy derivative (12-HOJA-Ile), a new wound-induced dicarboxyJasmonate, 12-carboxyjasmonoyl-l-isoleucine (12-HOOCJA-Ile) was discovered. HOJAs and 12-HOOCJA-Ile were enriched in the midveins of wounded leaves, strongly differentiating them from the other Jasmonate metabolites studied. The polarity of these oxylipins at physiological pH correlated with their appearance in midveins. When the time points of accumulation of different Jasmonates were determined, JA levels were found to increase within 2–5 min of wounding. Remarkably, these changes occurred throughout the plant and were not restricted to wounded leaves. The speed of the stimulus leading to JA accumulation in leaves distal to a wound is at least 3 cm/min. The data give new insights into the spatial and temporal accumulation of Jasmonates and have implications in the understanding of long-distance wound signaling in plants.
