丝裂原活化蛋白激酶(mitogen-activated protein kinases,MPKs)是植物中关键的信号调控因子,广泛参与生长发育、胁迫响应及激素信号传导等重要生理过程。作为MPK级联反应的下游效应分子,MPKs通过磷酸化作用调节特定底物,从而精准调控细...丝裂原活化蛋白激酶(mitogen-activated protein kinases,MPKs)是植物中关键的信号调控因子,广泛参与生长发育、胁迫响应及激素信号传导等重要生理过程。作为MPK级联反应的下游效应分子,MPKs通过磷酸化作用调节特定底物,从而精准调控细胞内多个生理过程,帮助植物迅速响应外界环境变化并提高适应能力。本文综述了近年来关于植物MPKs及其与底物相互作用的研究进展,分析了代表性MPKs与底物的作用机制及其对植物生理过程的影响。鉴于MPKs在不同植物物种中具有高度的保守性,本研究为其他植物的相关研究提供了重要的参考,并为植物MPKs信号传导的深入研究提供了新的视角。展开更多
Salt stress adversely affects plant growth,development,and crop yield.Rice(Oryza sativa L.)is one of the most salt-sensitive cereal crops,especially at the early seedling stage.Mitogen-activated protein kinase(MAPK/MP...Salt stress adversely affects plant growth,development,and crop yield.Rice(Oryza sativa L.)is one of the most salt-sensitive cereal crops,especially at the early seedling stage.Mitogen-activated protein kinase(MAPK/MPK)cascades have been shown to play critical roles in salt response in Arabidopsis.However,the roles of the MPK cascade signaling in rice salt response and substrates of Os MPK remain largely unknown.Here,we report that the salt-induced Os MPK4-Ideal Plant Architecture 1(IPA1)signaling pathway regulates the salt tolerance in rice.Under salt stress,Os MPK4 could interact with IPA1 and phosphorylate IPA1 at Thr180,leading to degradation of IPA1.Genetic evidence shows that IPA1 is a negative regulator of salt tolerance in rice,whereas Os MPK4 promotes salt response in an IPA1-dependent manner.Taken together,our results uncover an Os MPK4-IPA1 signal cascade that modulates the salt stress response in rice and sheds new light on the breeding of salt-tolerant rice varieties.展开更多
Mitogen-activated protein kinase （MAPK） cascades play important roles in regulating plant innate immune responses. In a genetic screen to search for mutants with constitutive defense responses, we identified multipl...Mitogen-activated protein kinase （MAPK） cascades play important roles in regulating plant innate immune responses. In a genetic screen to search for mutants with constitutive defense responses, we identified multiple alleles of mpk4 and mekkl that exhibit cell death and constitutive defense responses. Bimolecular fluorescence complemen- tation （BiFC） analysis showed that both MPK4 and MEKK1 interact with MKK1 and MKK2, two closely related MAPK kinases, mkkl and mkk2 single mutant plants do not have obvious mutant phenotypes. To test whether MKK1 and MKK2 function redundantly, mkkl mkk2 double mutants were generated. The mkkl mkk2 double mutant plants die at seedling stage and the seedling-lethality phenotype is temperature-dependent. Similar to the mpk4 and mekkl mutants, the mkkl mkk2 double mutant seedlings accumulate high levels of H202, display spontaneous cell death, constitutively express Pathogenesis Related （PR） genes and exhibit pathogen resistance. In addition, activation of MPK4 by fig22 is impaired in the mkkl mkk2 double mutants, suggesting that MKK1 and MKK2 function together with MPK4 and MEKK1 in a MAP kinase cascade to negatively regulate innate immune responses in plants.展开更多
Mitogen-activated protein kinase （MPK） cascades consist of a set of kinase types （MPKKKs, MPKKs, MPKs） to establish conserved signal-transducing modules mediating plant growth, development as well as responses to ...Mitogen-activated protein kinase （MPK） cascades consist of a set of kinase types （MPKKKs, MPKKs, MPKs） to establish conserved signal-transducing modules mediating plant growth, development as well as responses to internal and external cues. In this study, the expression patterns of six MPKKK, two MPKK, and 11 MPK genes in wheat in responses to external treatments of phytohormones, including naphthylacetic acid （NAA）, abscisic acid （ABA）, 6-benzyladenine （6-BA）, gibber- ellin （GA3）, salisylic acid （SA）, jasmonic acid （JA）, and ethylene （ETH）, were investigated. Expression analysis revealed that several of the MPK cascade genes are responses to the external phytohormone signaling. Of which, TaMPKKKA;3 is induced by 6-BA and NAA while TaMPK4 repressed by ETH, GA3, SA, and JA; TaMPKKKA, TaMPKKKA;3 and TaMPK1 are down-regulated by ETH and GA3whereas TaMPK9 and TaMPK12 repressed by ETH and JA in addition that TaMPK12 also repressed by GA3; TaMPK12;1 is down-regulated by ABA, GA3 and SA while TaMPK17 repressed by all exogenous phytonormones examined. TaMPK4, a MPK type gene previously characterized to mediate tolerance to phosphate （Pi） deprivation, was functionally evaluated for its role in mediation of responses of plants to exogenous GA3, ETH, SA, and JA. Results indicated that overexpression and antisense expression of TaMPK4 in tobacco dramatically modify the growth of seedlings upon treatments of GA3, SA and JA, in which the overexpressors behaved deteriorated growth feature whereas the seedlings with antisense expression of TaMPK4 exhibited improved seedling phenotype. The growth behaviors in lines overexpressing or antisensely expressing TaMPK4 are closely associated with the biomass and the corresponding hormone-associated parameters. These results demonstrated that TaMPK4 acts as a critical player in mediating the phyto- hormone signaling. Our findings have identified the phytohormone-responsive MPK cascade genes in wheat and provided a connection between the phytohormone-mediated responses and the MPK cascade pathways.展开更多
Mitogen-activated protein kinase(MAPK)cascades play important roles in disease resistance in model plant species.However,the functions of MAPK signaling pathways in crop disease resistance are largely unknown.Here we ...Mitogen-activated protein kinase(MAPK)cascades play important roles in disease resistance in model plant species.However,the functions of MAPK signaling pathways in crop disease resistance are largely unknown.Here we report the function of HvMKK1-HvMPK4-HvWRKY1 module in barley immune system.HvMPK4 is identified to play a negative role in barley immune response against Bgh,as virus-induced gene silencing of HvMPK4 results in enhanced disease resistance whilst stably overexpressing HvMPK4 leads to super-susceptibility to Bgh infection.Furthermore,the barley MAPK kinase HvMKK1 is found to specifically interact with HvMPK4,and the activated HvMKK1^(DD) variant specifically phosphorylates HvMPK4 in vitro.Moreover,the transcription factor HvWRKY1 is identified to be a downstream target of HvMPK4 and phosphorylated by HvMPK4 in vitro in the presence of HvMKK1^(DD).Phosphorylation assay coupled with mutagenesis analyses identifies S122,T284,and S347 in HvWRKY1 as the major residues phosphorylated by HvMPK4.HvWRKY1 is phosphorylated in barley at the early stages of Bgh infection,which enhances its suppression on barley immunity likely due to enhanced DNA-binding and transcriptional repression activity.Our data suggest that the HvMKK1-HvMPK4 kinase pair acts upstream of HvWRKY1 to negatively regulate barley immunity against powdery mildew.展开更多
Mitogen-activated protein kinases (MAPKs) are important components in signal transduction modules which play crucial roles in regulation of many biological processes in plants. Although genome-wide analysis of MAPK an...Mitogen-activated protein kinases (MAPKs) are important components in signal transduction modules which play crucial roles in regulation of many biological processes in plants. Although genome-wide analysis of MAPK and MAPKK family has been carried out in poplar species, few data about the biological function analysis of this gene family are available to date. In this study, a group C MAPK gene 84KMPK14 was cloned from hybrid poplar (Populus alba × P. glandulosa cv. “84K”). It contained a typical protein kinase domain, a conserved TEY-motif and an atypical conserved common docking (CD) domain. Sequence alignment revealed that 84KMPK14 was the most homologous to Populus trichocarpa PtMPK14. Expression analysis indicated that the transcript of 84KMPK14 in roots and young leaves was higher than that in other tissues. The expression of 84KMPK14 was down-regulated by low or high temperature and was induced by H2O2 significantly. It was suppressed by drought and salinity stresses slightly one hour after treatment and then increased quickly three hours after treatment. These results indicated that 84KMPK14 may be involved in environmental stresses, which provides basis for further characterization of the physiological analysis on this gene.展开更多
Dear Editor,Given the role of MYC2 as a pivotal regulator in the jasmonate(JA)signaling pathway,influencing the expression of a multitude of downstream genes(Zander et al.,2020),understanding the regulatory dynamics o...Dear Editor,Given the role of MYC2 as a pivotal regulator in the jasmonate(JA)signaling pathway,influencing the expression of a multitude of downstream genes(Zander et al.,2020),understanding the regulatory dynamics of MYC2 is essential for unraveling plant responses to stress conditions and hormonal signals.Previous studies on the regulation of MYC2 by MPK6 have reported conflicting findings.Takahashi et al.(2007)reported that MPK6 acts as a negative regulator of MYC2,whereas Sethi et al.(2014)proposed a positive regulatory role.Despite these findings,the precise genetic and biochemical mechanisms underlying the MPK6-MYC2 interaction remain poorly understood,highlighting the need for further investigation.展开更多
The plant cell wall is composed of a matrix of cellulose fibers, flexible pectin polymers, and an array of as- sorted carbohydrates and proteins. The receptor-like Wall-Associated Kinases （WAKs） of Arabidopsis bind ...The plant cell wall is composed of a matrix of cellulose fibers, flexible pectin polymers, and an array of as- sorted carbohydrates and proteins. The receptor-like Wall-Associated Kinases （WAKs） of Arabidopsis bind pectin in the wall, and are necessary both for cell expansion during development and for a response to pathogens and wounding. Mitogen Activated Protein Kinases （MPKs） form a major signaling link between cell surface receptors and both transcrip- tional and enzyme regulation in eukaryotes, and Arabidopsis MPK6 and MPK3 indeed have important roles in develop- ment and the response to stress and pathogens. A dominant allele of WAK2 requires kinase activity and activates a stress response that includes an increased ROS accumulation and the up-regulation of numerous genes involved in pathogen resistance, wounding, and cell wall biogenesis. This dominant allele requires a functional pectin binding and kinase domain, indicating that it is engaged in a WAK signaling pathway. A null mutant of the major plasma membrane ROS-producing enzyme complex, rbohd/f does not suppress the WAK2cTAP-induced phenotype. A mpk6, but not a mpk3, null allele is able to suppress the effects of this dominant WAK2 mutation, thus distinguishing MPK3 and MPK6, whose activity previously was thought to be redundant. Pectin activation of gene expression is abated in a wak2-null, but is tempered by the WAK-dominant allele that induces elevated basal stress-related transcript levels. The results suggest a mechanism in which changes to the cell wall can lead to a large change in cellular responses and help to explain how pathogens and wounding can have general effects on growth.展开更多
The plant signaling pathway that regulates pathogen-associated molecular pattern(PAMP)-triggered immunity(PTI)involves mitogen-activated protein kinase(MAPK)cascades that comprise sequential activation of several prot...The plant signaling pathway that regulates pathogen-associated molecular pattern(PAMP)-triggered immunity(PTI)involves mitogen-activated protein kinase(MAPK)cascades that comprise sequential activation of several protein kinases and the ensuing phosphorylation of MAPKs,which activate transcription factors(TFs)to promote downstream defense responses.To identify plant TFs that regulate MAPKs,we investigated TF-defective mutants of Arabidopsis thaliana and identified MYB44 as an essential constituent of the PTI pathway.MYB44 confers resistance against the bacterial pathogen Pseudomonas syringae by cooperating with MPK3 and MPK6.Under PAMP treatment,MYB44 binds to the promoters of MPK3 and MPK6 to activate their expression,leading to phosphorylation of MPK3 and MPK6 proteins.In turn,phosphorylated MPK3 and MPK6 phosphorylate MYB44 in a functionally redundant manner,thus enabling MYB44 to activate MPK3 and MPK6 expression and further activate downstream defense responses.Activation of defense responses has also been attributed to activation of EIN2 transcription by MYB44,which has previously been shown to affect PAMP recognition and PTI development.AtMYB44 thus functions as an integral component of the PTI pathway by connecting transcriptional and posttranscriptional regulation of the MPK3/6 cascade.展开更多
文摘丝裂原活化蛋白激酶(mitogen-activated protein kinases,MPKs)是植物中关键的信号调控因子,广泛参与生长发育、胁迫响应及激素信号传导等重要生理过程。作为MPK级联反应的下游效应分子,MPKs通过磷酸化作用调节特定底物,从而精准调控细胞内多个生理过程,帮助植物迅速响应外界环境变化并提高适应能力。本文综述了近年来关于植物MPKs及其与底物相互作用的研究进展,分析了代表性MPKs与底物的作用机制及其对植物生理过程的影响。鉴于MPKs在不同植物物种中具有高度的保守性,本研究为其他植物的相关研究提供了重要的参考,并为植物MPKs信号传导的深入研究提供了新的视角。
基金supported by the National Natural Science Foundation of China (31788103, 32122064, 32122012)the Chinese Academy of Sciences (XDA24030504, 2019099)+1 种基金China Agricultural Research System (CARS-01-4)the China Postdoctoral Science Foundation (2019M650885)
文摘Salt stress adversely affects plant growth,development,and crop yield.Rice(Oryza sativa L.)is one of the most salt-sensitive cereal crops,especially at the early seedling stage.Mitogen-activated protein kinase(MAPK/MPK)cascades have been shown to play critical roles in salt response in Arabidopsis.However,the roles of the MPK cascade signaling in rice salt response and substrates of Os MPK remain largely unknown.Here,we report that the salt-induced Os MPK4-Ideal Plant Architecture 1(IPA1)signaling pathway regulates the salt tolerance in rice.Under salt stress,Os MPK4 could interact with IPA1 and phosphorylate IPA1 at Thr180,leading to degradation of IPA1.Genetic evidence shows that IPA1 is a negative regulator of salt tolerance in rice,whereas Os MPK4 promotes salt response in an IPA1-dependent manner.Taken together,our results uncover an Os MPK4-IPA1 signal cascade that modulates the salt stress response in rice and sheds new light on the breeding of salt-tolerant rice varieties.
文摘Mitogen-activated protein kinase （MAPK） cascades play important roles in regulating plant innate immune responses. In a genetic screen to search for mutants with constitutive defense responses, we identified multiple alleles of mpk4 and mekkl that exhibit cell death and constitutive defense responses. Bimolecular fluorescence complemen- tation （BiFC） analysis showed that both MPK4 and MEKK1 interact with MKK1 and MKK2, two closely related MAPK kinases, mkkl and mkk2 single mutant plants do not have obvious mutant phenotypes. To test whether MKK1 and MKK2 function redundantly, mkkl mkk2 double mutants were generated. The mkkl mkk2 double mutant plants die at seedling stage and the seedling-lethality phenotype is temperature-dependent. Similar to the mpk4 and mekkl mutants, the mkkl mkk2 double mutant seedlings accumulate high levels of H202, display spontaneous cell death, constitutively express Pathogenesis Related （PR） genes and exhibit pathogen resistance. In addition, activation of MPK4 by fig22 is impaired in the mkkl mkk2 double mutants, suggesting that MKK1 and MKK2 function together with MPK4 and MEKK1 in a MAP kinase cascade to negatively regulate innate immune responses in plants.
基金financially supported by the National Natural Science Foundation of China (31371618,31201674)the National Transgenic Major Program of China (2011ZX08008)the Key Laboratory of Crop Growth Regulation of Hebei Province,China
文摘Mitogen-activated protein kinase （MPK） cascades consist of a set of kinase types （MPKKKs, MPKKs, MPKs） to establish conserved signal-transducing modules mediating plant growth, development as well as responses to internal and external cues. In this study, the expression patterns of six MPKKK, two MPKK, and 11 MPK genes in wheat in responses to external treatments of phytohormones, including naphthylacetic acid （NAA）, abscisic acid （ABA）, 6-benzyladenine （6-BA）, gibber- ellin （GA3）, salisylic acid （SA）, jasmonic acid （JA）, and ethylene （ETH）, were investigated. Expression analysis revealed that several of the MPK cascade genes are responses to the external phytohormone signaling. Of which, TaMPKKKA;3 is induced by 6-BA and NAA while TaMPK4 repressed by ETH, GA3, SA, and JA; TaMPKKKA, TaMPKKKA;3 and TaMPK1 are down-regulated by ETH and GA3whereas TaMPK9 and TaMPK12 repressed by ETH and JA in addition that TaMPK12 also repressed by GA3; TaMPK12;1 is down-regulated by ABA, GA3 and SA while TaMPK17 repressed by all exogenous phytonormones examined. TaMPK4, a MPK type gene previously characterized to mediate tolerance to phosphate （Pi） deprivation, was functionally evaluated for its role in mediation of responses of plants to exogenous GA3, ETH, SA, and JA. Results indicated that overexpression and antisense expression of TaMPK4 in tobacco dramatically modify the growth of seedlings upon treatments of GA3, SA and JA, in which the overexpressors behaved deteriorated growth feature whereas the seedlings with antisense expression of TaMPK4 exhibited improved seedling phenotype. The growth behaviors in lines overexpressing or antisensely expressing TaMPK4 are closely associated with the biomass and the corresponding hormone-associated parameters. These results demonstrated that TaMPK4 acts as a critical player in mediating the phyto- hormone signaling. Our findings have identified the phytohormone-responsive MPK cascade genes in wheat and provided a connection between the phytohormone-mediated responses and the MPK cascade pathways.
基金funded by the National Key R&D Program of China(2018YFD1000703 and 2018YFD1000700)the Strategic Priority Research Program of Chinese Academy of Sciences(XDPB16)National Program on Research and Development of Transgenic Plants(2016ZX08009-003-001).
文摘Mitogen-activated protein kinase(MAPK)cascades play important roles in disease resistance in model plant species.However,the functions of MAPK signaling pathways in crop disease resistance are largely unknown.Here we report the function of HvMKK1-HvMPK4-HvWRKY1 module in barley immune system.HvMPK4 is identified to play a negative role in barley immune response against Bgh,as virus-induced gene silencing of HvMPK4 results in enhanced disease resistance whilst stably overexpressing HvMPK4 leads to super-susceptibility to Bgh infection.Furthermore,the barley MAPK kinase HvMKK1 is found to specifically interact with HvMPK4,and the activated HvMKK1^(DD) variant specifically phosphorylates HvMPK4 in vitro.Moreover,the transcription factor HvWRKY1 is identified to be a downstream target of HvMPK4 and phosphorylated by HvMPK4 in vitro in the presence of HvMKK1^(DD).Phosphorylation assay coupled with mutagenesis analyses identifies S122,T284,and S347 in HvWRKY1 as the major residues phosphorylated by HvMPK4.HvWRKY1 is phosphorylated in barley at the early stages of Bgh infection,which enhances its suppression on barley immunity likely due to enhanced DNA-binding and transcriptional repression activity.Our data suggest that the HvMKK1-HvMPK4 kinase pair acts upstream of HvWRKY1 to negatively regulate barley immunity against powdery mildew.
文摘Mitogen-activated protein kinases (MAPKs) are important components in signal transduction modules which play crucial roles in regulation of many biological processes in plants. Although genome-wide analysis of MAPK and MAPKK family has been carried out in poplar species, few data about the biological function analysis of this gene family are available to date. In this study, a group C MAPK gene 84KMPK14 was cloned from hybrid poplar (Populus alba × P. glandulosa cv. “84K”). It contained a typical protein kinase domain, a conserved TEY-motif and an atypical conserved common docking (CD) domain. Sequence alignment revealed that 84KMPK14 was the most homologous to Populus trichocarpa PtMPK14. Expression analysis indicated that the transcript of 84KMPK14 in roots and young leaves was higher than that in other tissues. The expression of 84KMPK14 was down-regulated by low or high temperature and was induced by H2O2 significantly. It was suppressed by drought and salinity stresses slightly one hour after treatment and then increased quickly three hours after treatment. These results indicated that 84KMPK14 may be involved in environmental stresses, which provides basis for further characterization of the physiological analysis on this gene.
基金This research was supported by the DOE Great Lakes Bioenergy Research Center(DOE BER Office of Science DE-SC0018409),the Brain Pool Program by the Ministry of Science and ICT through the National Research Foundation(NRF)of Korea(RS-2023-00262576),and the National Research Foundation of Korea(NRF-2023R1A2C1004193).M.-Y.J.was additionally supported by an NRF grant funded by the Korean government(Ministry of Science and ICT)(RS-2025000518246).
文摘Dear Editor,Given the role of MYC2 as a pivotal regulator in the jasmonate(JA)signaling pathway,influencing the expression of a multitude of downstream genes(Zander et al.,2020),understanding the regulatory dynamics of MYC2 is essential for unraveling plant responses to stress conditions and hormonal signals.Previous studies on the regulation of MYC2 by MPK6 have reported conflicting findings.Takahashi et al.(2007)reported that MPK6 acts as a negative regulator of MYC2,whereas Sethi et al.(2014)proposed a positive regulatory role.Despite these findings,the precise genetic and biochemical mechanisms underlying the MPK6-MYC2 interaction remain poorly understood,highlighting the need for further investigation.
文摘The plant cell wall is composed of a matrix of cellulose fibers, flexible pectin polymers, and an array of as- sorted carbohydrates and proteins. The receptor-like Wall-Associated Kinases （WAKs） of Arabidopsis bind pectin in the wall, and are necessary both for cell expansion during development and for a response to pathogens and wounding. Mitogen Activated Protein Kinases （MPKs） form a major signaling link between cell surface receptors and both transcrip- tional and enzyme regulation in eukaryotes, and Arabidopsis MPK6 and MPK3 indeed have important roles in develop- ment and the response to stress and pathogens. A dominant allele of WAK2 requires kinase activity and activates a stress response that includes an increased ROS accumulation and the up-regulation of numerous genes involved in pathogen resistance, wounding, and cell wall biogenesis. This dominant allele requires a functional pectin binding and kinase domain, indicating that it is engaged in a WAK signaling pathway. A null mutant of the major plasma membrane ROS-producing enzyme complex, rbohd/f does not suppress the WAK2cTAP-induced phenotype. A mpk6, but not a mpk3, null allele is able to suppress the effects of this dominant WAK2 mutation, thus distinguishing MPK3 and MPK6, whose activity previously was thought to be redundant. Pectin activation of gene expression is abated in a wak2-null, but is tempered by the WAK-dominant allele that induces elevated basal stress-related transcript levels. The results suggest a mechanism in which changes to the cell wall can lead to a large change in cellular responses and help to explain how pathogens and wounding can have general effects on growth.
基金supported by the Natural Science Foundation of China(grant numbers 31772247,32072399,32170202)the Natural Science Foundation of Shandong Province(grant numbers ZR2020MC113,ZR2020MC120,ZR2020QC126).
文摘The plant signaling pathway that regulates pathogen-associated molecular pattern(PAMP)-triggered immunity(PTI)involves mitogen-activated protein kinase(MAPK)cascades that comprise sequential activation of several protein kinases and the ensuing phosphorylation of MAPKs,which activate transcription factors(TFs)to promote downstream defense responses.To identify plant TFs that regulate MAPKs,we investigated TF-defective mutants of Arabidopsis thaliana and identified MYB44 as an essential constituent of the PTI pathway.MYB44 confers resistance against the bacterial pathogen Pseudomonas syringae by cooperating with MPK3 and MPK6.Under PAMP treatment,MYB44 binds to the promoters of MPK3 and MPK6 to activate their expression,leading to phosphorylation of MPK3 and MPK6 proteins.In turn,phosphorylated MPK3 and MPK6 phosphorylate MYB44 in a functionally redundant manner,thus enabling MYB44 to activate MPK3 and MPK6 expression and further activate downstream defense responses.Activation of defense responses has also been attributed to activation of EIN2 transcription by MYB44,which has previously been shown to affect PAMP recognition and PTI development.AtMYB44 thus functions as an integral component of the PTI pathway by connecting transcriptional and posttranscriptional regulation of the MPK3/6 cascade.
