Seed germination is a complex trait regulated by multiple genes in rice.However,the regulators of rice seed germination have yet to be sufficiently determined.Here,a quantitative trait locus(QTL)for rice seed germinat...Seed germination is a complex trait regulated by multiple genes in rice.However,the regulators of rice seed germination have yet to be sufficiently determined.Here,a quantitative trait locus(QTL)for rice seed germination was identified in a genome-wide association study.The candidate gene JASMONATE ZIM-DOMAIN 5(OsJAZ5)of the QTL was verified that positively regulates seed germination.OsJAZ5 regulation of seed germination involves an OsABI3-mediated abscisic acid pathway.Overexpression of OsJAZ5 facilitated seed germination.The application of OsJAZ5 might be useful for increasing seed germination for rice direct seeding.展开更多
The Arabidopsis Jasmonate ZIM-domain proteins （JAZs） act as substrates of SCF complex to repress their downstream targets, which are essential for JA-regulated plant development and defense. The bHLH transcription f...The Arabidopsis Jasmonate ZIM-domain proteins （JAZs） act as substrates of SCF complex to repress their downstream targets, which are essential for JA-regulated plant development and defense. The bHLH transcription factor MYC2 was found to interact with JAZs and mediate JA responses including JA-inhibitory root growth. Here, we identified another bHLH transcription factor MYC3 which directly interacted with JAZs by virtue of its N-terminal region to regulate JA responses. The transgenic plants with overexpression of MYC3 exhibited hypersensitivity in JA-inhibitory root elon- gation and seedling development. The JAZ-interacting pattern and the JA-induced expression pattern of MYC3 were distinguishable from those of MYC2. We speculate that MYC3 and MYC2 may have redundant but also distinguishable functions in regulation of JA responses.展开更多
Suppression mechanisms mediated by transcriptional repressors commonly exist in diverse phytohormone signaling pathways.In Arabidopsis thaliana,JASMONATE-ZIM DOMAIN(JAZ)proteins are transcriptional repressors that fun...Suppression mechanisms mediated by transcriptional repressors commonly exist in diverse phytohormone signaling pathways.In Arabidopsis thaliana,JASMONATE-ZIM DOMAIN(JAZ)proteins are transcriptional repressors that function as negative regulators of diverse JA responses.Novel Interactor of JAZ(NINJA)is an adaptor protein connecting JAZs with the co-repressor,TOPLESS(TPL),to mediate gene repression in JA-dependent root growth inhibition and defense pathways.However,whether NINJA or other adaptor proteins are employed in other JA-responsive biological processes remains to be elucidated.In the present study,we demonstrate that a previously uncharacterized protein,ECAP(EAR motif-Containing Adaptor Protein),directly interacts with JAZ6 and JAZ8 and enhances their transcriptional repression activities.We provide evidence that ECAP is a novel adaptor protein for JAZ6/8 recruitment of the transcriptional co-repressor,TOPLESS-RELATED 2(TPR2),into a transcriptional repressor complex that represses the WD-repeat/bHLH/MYB complex,an important transcriptional activator in the JA-dependent anthocyanin biosynthesis pathway.Our findings,together with previous reports,reveal that specific adaptor proteins play a critical role in distinct JA responses by pairing different JAZs(which possess overlapping but also specific functions)with the general co-repressors,TPL and TPRs.展开更多
The phytohormones ethylene(ET)and jasmonate(JA)regulate plant development,growth,and defense responses;however,the molecular basis for their signaling crosstalk is unclear.Here,we show that JA-ZIM-domain(JAZ)proteins,...The phytohormones ethylene(ET)and jasmonate(JA)regulate plant development,growth,and defense responses;however,the molecular basis for their signaling crosstalk is unclear.Here,we show that JA-ZIM-domain(JAZ)proteins,which repress JA signaling,repress trichome initiation/branching and anthocyanin accumulation,and inhibit the transcriptional activity of the basic helix-loop-helix(bHLH)-MYBmembers(GLABRA3(GL3)-GL1 and TRANSPARENT TESTA 8(TT8)-MYB75)of WD-repeat/bHLH/MYB(WBM)complexes.The ET-stabilized transcription factors ETHYLENEINSENSITIVE3(EIN3)and EIN3-LIKE1(EIL1)were found to bind to several members of WBM complexes,including GL3,ENHANCER OF GLABRA3(EGL3),TT8,GL1,MYB75,and TRANSPARENT TESTA GLABRA1(TTG1).This binding repressed the transcriptional activity of the b HLH-MYB proteins and inhibited anthocyanin accumulation,trichome formation,and defenses against insect herbivores while promoting root hair formation.Conversely,the JA-activated b HLH members GL3,EGL3,and TT8 of WBM complexes were able to interact with and attenuate the transcriptional activity of EIN3/EIL1 at the HOOKLESS1 promoter,and their overexpression inhibited apical hook formation.Thus,this study demonstrates a molecular framework for signaling crosstalk between JA and ET in plant development,secondary metabolism,and defense responses.展开更多
Jasmonate(JA)regulates various aspects of plant growth and development and stress responses,with prominent roles in male reproductive development and defenses against herbivores and necrotrophic pathogens.JASMONATE-ZI...Jasmonate(JA)regulates various aspects of plant growth and development and stress responses,with prominent roles in male reproductive development and defenses against herbivores and necrotrophic pathogens.JASMONATE-ZIM DOMAIN(JAZ)proteins are key regulators in the JA signaling pathway and function to repress the expression of JA-responsive genes.Here,we show that JAZ proteins directly interact with several chromatin-associated Polycomb proteins to mediate repressive chromatin modifications at JA-responsive genes and,thus,their transcriptional repression in Arabidopsis.Genetic analyses revealed that the developmental defects,including anther and pollen abnormalities,resulting from loss or block of JA signaling were partially rescued by loss of Polycomb protein-mediated chromatin silencing(Polycomb repression).We further found that JAZ-mediated transcriptional repression during anther and pollen development requires Polycomb proteins at four key Regulatory loci.Analysis of genome-wide occupancy of a Polycomb factor and transcriptome reprogramming in response to JA revealed that Polycomb repression is involved in the repression of various JA-responsive genes.Taken together,our study reveals an important chromatin-based mechanism for JAZ-mediated transcriptional repression and JA signaling in plants.展开更多
Jasmonates(JAs) are phytohormones that finely regulate critical biological processes, including plant development and defense. JASMONATE ZIM-DOMAIN(JAZ) proteins are crucial transcriptional regulators that keep JA-res...Jasmonates(JAs) are phytohormones that finely regulate critical biological processes, including plant development and defense. JASMONATE ZIM-DOMAIN(JAZ) proteins are crucial transcriptional regulators that keep JA-responsive genes in a repressed state. In the presence of JA-Ile, JAZ repressors are ubiquitinated and targeted for degradation by the ubiquitin/proteasome system,allowing the activation of downstream transcription factors and, consequently, the induction of JA-responsive genes. A growing body of evidence has shown that JA signaling is crucial in defending against plant viruses and their insect vectors. Here, we describe the interaction of C2proteins from two tomato-infecting geminiviruses from the genus Begomovirus, tomato yellow leaf curl virus(TYLCV) and tomato yellow curl Sardinia virus(TYLCSaV), with the transcriptional repressor JAZ8 from Arabidopsis thaliana and its closest orthologue in tomato, SlJAZ9. Both JAZ and C2proteins colocalize in the nucleus, forming discrete nuclear speckles. Overexpression of JAZ8did not lead to altered responses to TYLCV infection in Arabidopsis;however, knock-down of JAZ8 favors geminiviral infection. Low levels of JAZ8 likely affect the viral infection specifically,since JAZ8-silenced plants neither display obvious developmental phenotypes nor present differences in their interaction with the viral insect vector. In summary, our results show that the geminivirus-encoded C2 interacts with JAZ8 in the nucleus, and suggest that this plant protein exerts an anti-geminiviral effect.展开更多
Jasmonates （JAs） are plant hormones with essential roles in plant defense and development. The basic- helix-loop-helix （bHLH） transcription factor （TF） MYC2 has recently emerged as a master regulator of most asp...Jasmonates （JAs） are plant hormones with essential roles in plant defense and development. The basic- helix-loop-helix （bHLH） transcription factor （TF） MYC2 has recently emerged as a master regulator of most aspects of the jasmonate （JA） signaling pathway in Arabidopsis. MYC2 coordinates JA-mediated defense responses by antagonistically regulating two different branches of the JA signaling pathway that determine resistance to pests and pathogens, respectively. MYC2 is required for induced systemic resistance （ISR） triggered by beneficial soil microbes while MYC2 function is targeted by pathogens during effector-mediated suppression of innate immunity in roots. Another notable function of MYC2 is the regulation of crosstalk between the signaling pathways of JA and those of other phytohormones such as abscisic acid （ABA）, salicylic acid （SA）, gibberellins （GAs）, and auxin （IAA）. MYC2 also regulates interactions between JA signaling and light, phytochrome signaling, and the circadian clock, MYC2 is involved in JA-regulated plant development, lateral and adventitious root formation, flowering time, and shade avoidance syndrome. Related bHLH TFs MYC3 and MYC4 also regulate both overlapping and distinct MYC2-regulated functions in Arabidopsis while MYC2 orthologs act as ＇master switches＇ that regulate JA-mediated biosynthesis of secondary metabolites. Here, we briefly review recent studies that revealed mechanistic new insights into the mode of action of this versatile TF.展开更多
基金supported by the Hainan Province Science and Technology Special Fund,China(ZDYF2023XDNY086)the Project of Sanya Yazhou Bay Science and Technology City,China(SCKJ-JYRC-2022-87)+1 种基金the Natural Science Foundation of Guangdong Province,China(2023A1515012052,2023A1515012092)the Science and Technology Project of Guangzhou,China(2023A04J0749,2023A04J1452).
文摘Seed germination is a complex trait regulated by multiple genes in rice.However,the regulators of rice seed germination have yet to be sufficiently determined.Here,a quantitative trait locus(QTL)for rice seed germination was identified in a genome-wide association study.The candidate gene JASMONATE ZIM-DOMAIN 5(OsJAZ5)of the QTL was verified that positively regulates seed germination.OsJAZ5 regulation of seed germination involves an OsABI3-mediated abscisic acid pathway.Overexpression of OsJAZ5 facilitated seed germination.The application of OsJAZ5 might be useful for increasing seed germination for rice direct seeding.
文摘The Arabidopsis Jasmonate ZIM-domain proteins （JAZs） act as substrates of SCF complex to repress their downstream targets, which are essential for JA-regulated plant development and defense. The bHLH transcription factor MYC2 was found to interact with JAZs and mediate JA responses including JA-inhibitory root growth. Here, we identified another bHLH transcription factor MYC3 which directly interacted with JAZs by virtue of its N-terminal region to regulate JA responses. The transgenic plants with overexpression of MYC3 exhibited hypersensitivity in JA-inhibitory root elon- gation and seedling development. The JAZ-interacting pattern and the JA-induced expression pattern of MYC3 were distinguishable from those of MYC2. We speculate that MYC3 and MYC2 may have redundant but also distinguishable functions in regulation of JA responses.
基金supported by the National Natural Science Foundation of China(grant no.31872662 and 91854119 to Y.F.)China Postdoctoral Science Foundation grant(2018M641532 to C.L.).
文摘Suppression mechanisms mediated by transcriptional repressors commonly exist in diverse phytohormone signaling pathways.In Arabidopsis thaliana,JASMONATE-ZIM DOMAIN(JAZ)proteins are transcriptional repressors that function as negative regulators of diverse JA responses.Novel Interactor of JAZ(NINJA)is an adaptor protein connecting JAZs with the co-repressor,TOPLESS(TPL),to mediate gene repression in JA-dependent root growth inhibition and defense pathways.However,whether NINJA or other adaptor proteins are employed in other JA-responsive biological processes remains to be elucidated.In the present study,we demonstrate that a previously uncharacterized protein,ECAP(EAR motif-Containing Adaptor Protein),directly interacts with JAZ6 and JAZ8 and enhances their transcriptional repression activities.We provide evidence that ECAP is a novel adaptor protein for JAZ6/8 recruitment of the transcriptional co-repressor,TOPLESS-RELATED 2(TPR2),into a transcriptional repressor complex that represses the WD-repeat/bHLH/MYB complex,an important transcriptional activator in the JA-dependent anthocyanin biosynthesis pathway.Our findings,together with previous reports,reveal that specific adaptor proteins play a critical role in distinct JA responses by pairing different JAZs(which possess overlapping but also specific functions)with the general co-repressors,TPL and TPRs.
基金supported by the National Natural Science Foundation of China(31400254 and 31670315)Tsinghua University Initiative Scientific Research Program+3 种基金the grant from Beijing Municipal Commission of Education and Beijing Natural Science Foundation(KZ202210028044)the Beijing Nova Program(Z171100001117037)the funding from the Tsinghua-Peking Center for Life Sciencesthe Project of Graduate Student Academic Innovation of Capital Normal University(010-2255074)。
文摘The phytohormones ethylene(ET)and jasmonate(JA)regulate plant development,growth,and defense responses;however,the molecular basis for their signaling crosstalk is unclear.Here,we show that JA-ZIM-domain(JAZ)proteins,which repress JA signaling,repress trichome initiation/branching and anthocyanin accumulation,and inhibit the transcriptional activity of the basic helix-loop-helix(bHLH)-MYBmembers(GLABRA3(GL3)-GL1 and TRANSPARENT TESTA 8(TT8)-MYB75)of WD-repeat/bHLH/MYB(WBM)complexes.The ET-stabilized transcription factors ETHYLENEINSENSITIVE3(EIN3)and EIN3-LIKE1(EIL1)were found to bind to several members of WBM complexes,including GL3,ENHANCER OF GLABRA3(EGL3),TT8,GL1,MYB75,and TRANSPARENT TESTA GLABRA1(TTG1).This binding repressed the transcriptional activity of the b HLH-MYB proteins and inhibited anthocyanin accumulation,trichome formation,and defenses against insect herbivores while promoting root hair formation.Conversely,the JA-activated b HLH members GL3,EGL3,and TT8 of WBM complexes were able to interact with and attenuate the transcriptional activity of EIN3/EIL1 at the HOOKLESS1 promoter,and their overexpression inhibited apical hook formation.Thus,this study demonstrates a molecular framework for signaling crosstalk between JA and ET in plant development,secondary metabolism,and defense responses.
基金supported in part by funding from Chinese Academy of Sciences,National Natural Foundation of China(grant no.31970533)Peking University Institute of Advanced Agricultural Sciences.
文摘Jasmonate(JA)regulates various aspects of plant growth and development and stress responses,with prominent roles in male reproductive development and defenses against herbivores and necrotrophic pathogens.JASMONATE-ZIM DOMAIN(JAZ)proteins are key regulators in the JA signaling pathway and function to repress the expression of JA-responsive genes.Here,we show that JAZ proteins directly interact with several chromatin-associated Polycomb proteins to mediate repressive chromatin modifications at JA-responsive genes and,thus,their transcriptional repression in Arabidopsis.Genetic analyses revealed that the developmental defects,including anther and pollen abnormalities,resulting from loss or block of JA signaling were partially rescued by loss of Polycomb protein-mediated chromatin silencing(Polycomb repression).We further found that JAZ-mediated transcriptional repression during anther and pollen development requires Polycomb proteins at four key Regulatory loci.Analysis of genome-wide occupancy of a Polycomb factor and transcriptome reprogramming in response to JA revealed that Polycomb repression is involved in the repression of various JA-responsive genes.Taken together,our study reveals an important chromatin-based mechanism for JAZ-mediated transcriptional repression and JA signaling in plants.
基金supported by a President's International Fellowship Initiative (PIFI) postdoctoral fel owship (No. 2016PB042) from the Chinese Academy of Sciencesthe “Programa Juan de la Cierva” (IJCI-2017-33367) from the MCIN and FEDER program UMA20-FEDERJA-132 by AEI and by “ERDF A way of making Europe,” by the “European Union”Funding for Open Access charge: Universidad de Málaga / CBUA。
文摘Jasmonates(JAs) are phytohormones that finely regulate critical biological processes, including plant development and defense. JASMONATE ZIM-DOMAIN(JAZ) proteins are crucial transcriptional regulators that keep JA-responsive genes in a repressed state. In the presence of JA-Ile, JAZ repressors are ubiquitinated and targeted for degradation by the ubiquitin/proteasome system,allowing the activation of downstream transcription factors and, consequently, the induction of JA-responsive genes. A growing body of evidence has shown that JA signaling is crucial in defending against plant viruses and their insect vectors. Here, we describe the interaction of C2proteins from two tomato-infecting geminiviruses from the genus Begomovirus, tomato yellow leaf curl virus(TYLCV) and tomato yellow curl Sardinia virus(TYLCSaV), with the transcriptional repressor JAZ8 from Arabidopsis thaliana and its closest orthologue in tomato, SlJAZ9. Both JAZ and C2proteins colocalize in the nucleus, forming discrete nuclear speckles. Overexpression of JAZ8did not lead to altered responses to TYLCV infection in Arabidopsis;however, knock-down of JAZ8 favors geminiviral infection. Low levels of JAZ8 likely affect the viral infection specifically,since JAZ8-silenced plants neither display obvious developmental phenotypes nor present differences in their interaction with the viral insect vector. In summary, our results show that the geminivirus-encoded C2 interacts with JAZ8 in the nucleus, and suggest that this plant protein exerts an anti-geminiviral effect.
文摘Jasmonates （JAs） are plant hormones with essential roles in plant defense and development. The basic- helix-loop-helix （bHLH） transcription factor （TF） MYC2 has recently emerged as a master regulator of most aspects of the jasmonate （JA） signaling pathway in Arabidopsis. MYC2 coordinates JA-mediated defense responses by antagonistically regulating two different branches of the JA signaling pathway that determine resistance to pests and pathogens, respectively. MYC2 is required for induced systemic resistance （ISR） triggered by beneficial soil microbes while MYC2 function is targeted by pathogens during effector-mediated suppression of innate immunity in roots. Another notable function of MYC2 is the regulation of crosstalk between the signaling pathways of JA and those of other phytohormones such as abscisic acid （ABA）, salicylic acid （SA）, gibberellins （GAs）, and auxin （IAA）. MYC2 also regulates interactions between JA signaling and light, phytochrome signaling, and the circadian clock, MYC2 is involved in JA-regulated plant development, lateral and adventitious root formation, flowering time, and shade avoidance syndrome. Related bHLH TFs MYC3 and MYC4 also regulate both overlapping and distinct MYC2-regulated functions in Arabidopsis while MYC2 orthologs act as ＇master switches＇ that regulate JA-mediated biosynthesis of secondary metabolites. Here, we briefly review recent studies that revealed mechanistic new insights into the mode of action of this versatile TF.
