Drought stress severely limits rice productivity.Understanding of drought-response mechanisms in rice is essential for developing climate-resilient varieties.While cysteine-rich receptor-like kinases(CRKs)are primaril...Drought stress severely limits rice productivity.Understanding of drought-response mechanisms in rice is essential for developing climate-resilient varieties.While cysteine-rich receptor-like kinases(CRKs)are primarily implicated in plant development and immunity,their role in drought response remains poorly understood.In this study,we identified a CRK,OsCRK14,as a key positive regulator of drought resistance in rice.We demonstrated that plasma membrane-localized OsCRK14 phosphorylates the receptor-like cytoplasmic kinase OsRLCK57 under drought stress,leading to activate a mitogen-activated protein kinase(MAPK)cascade(OsMKKK10-OsMKK4-OsMPK6).Activated OsMPK6 directly phosphorylates the abscisic acid-responsive transcription factor OsbZIP66 at conserved Serine-Proline/Threonine-Proline motifs,enhancing its stability and promoting drought-responsive gene expression.Furthermore,we found that natural variations in the OsCRK14 promoter influence its transcript levels due to the altered OsMYB72 binding affinities,which are correlated with drought-resistance differences among rice varieties.Collectively,our study discovers a novel CRK-RLCK-MAPK-bZIP signaling pathway that connects membrane signal sensing to transcriptional regulation in drought response,providing both mechanistic insights and genetic resources for breeding drought-resistant rice.展开更多
[目的]对拟南芥类受体胞质激酶RBK2(ROP binding protein kinases 2)的结构、分子进化和基因表达等进行预测分析。[方法]利用生物信息学在线相关数据库和分析软件对目的蛋白的基本理化性质、二级及三级结构、同源性、基因表达、蛋白定...[目的]对拟南芥类受体胞质激酶RBK2(ROP binding protein kinases 2)的结构、分子进化和基因表达等进行预测分析。[方法]利用生物信息学在线相关数据库和分析软件对目的蛋白的基本理化性质、二级及三级结构、同源性、基因表达、蛋白定位、相互作用蛋白进行分析预测。[结果]拟南芥类受体胞质激酶RBK2是一个亲水性不稳定蛋白,主要构成原件为α螺旋及β片状折叠,进化树构建及多序列比对显示其与琴叶拟南芥中名为激酶家族蛋白的蛋白进化距离最近。主要存在于细胞质和细胞核中,其编码基因在成熟花粉中强烈表达,且RBK2与PP2C家族蛋白有较强的相互作用。[结论]拟南芥RBK2很可能通过参与信号转导途径在植物种子萌发、花粉成熟及细胞分裂等方面发挥重要作用。展开更多
In angiosperms,the pollen tube enters the receptive synergid cell,where it ruptures to release its cytoplasm along with two sperm cells.This interaction is complex,and the exact signal transducers that trigger the bur...In angiosperms,the pollen tube enters the receptive synergid cell,where it ruptures to release its cytoplasm along with two sperm cells.This interaction is complex,and the exact signal transducers that trigger the bursting of pollen tubes are not well understood.In this study,we identify three homologous receptor-like cytoplasmic kinases(RLCKs)expressed in pollen tubes of Arabidopsis,Delayed Burst 1/2/3(DEB1/2/3),which play a crucial role in this process.These genes produce proteins localized on the plasma membrane,and their knockout causes delayed pollen tube burst and entrance of additional pollen tubes into the embryo sac due to fertilization recovery.We show that DEBs interact with the Ca^(2+)pump ACA9,influencing the dynamics of cytoplasmic Ca^(2+)in pollen tubes through phosphorylation.These results highlight the importance of DEBs as key signal transducers and the critical function of the DEB-ACA9 axis in timely pollen tube burst in synergids.展开更多
Receptor-like cytoplasmic kinases （RLCKs） in plants belong to the super family of receptor-like kinases （RLKs）. These proteins show homology to RLKs in kinase domain but lack the transmembrane domain. Some of the ...Receptor-like cytoplasmic kinases （RLCKs） in plants belong to the super family of receptor-like kinases （RLKs）. These proteins show homology to RLKs in kinase domain but lack the transmembrane domain. Some of the functionally characterized RLCKs from plants have been shown to play roles in development and stress responses. Previously, 149 and 187 RLCK encoding genes were identified from Arabidopsis and rice, respectively. By using HMM-based domain structure and phylogenetic relationships, we have identified 379 OsRLCKs from rice. OsRLCKs are distributed on all 12 chromosomes of rice and some members are located on duplicated chromosomal segments. Several OsRLCKs probably also undergo alternative splicing, some having evidence only in the form of gene models. To understand their possible functions, expression patterns during landmark stages of vegetative and reproductive development as well as abiotic and biotic stress using microarray and MPSS-based data were analyzed. Real-time PCR-based expression profiling for a selected few genes confirmed the outcome of microarray analysis. Differential expression patterns observed for majority of OsRLCKs during development and stress suggest their involvement in diverse functions in rice. Majority of the stress-responsive OsRLCKs were also found to be localized within mapped regions of abiotic stress QTLs. Outcome of this study would help in selecting organ/development stage specific OsRLCK genes/targets for functional validation studies.展开更多
The orderly deposition of secondary cell wall(SCW)in plants is implicated in various biological programs and is precisely controlled.Although many positive and negative regulators of SCW have been documented,the molec...The orderly deposition of secondary cell wall(SCW)in plants is implicated in various biological programs and is precisely controlled.Although many positive and negative regulators of SCW have been documented,the molecular mechanisms underlying SCW formation coordinated with distinct cellular physiological processes during plant adaptive growth remain largely unclear.Here,we report the identification of Cellulose Synthase co-expressed Kinase1(CSK1),which encodes a receptor-like cytoplasmic kinase,as a negative regulator of SCW formation and its signaling cascade in rice.Transcriptome deep sequencing of developing internodes and genome-wide co-expression assays revealed that CSK1 is co-expressed with cellulose synthase genes and is responsive to various stress stimuli.The increased SCW thickness and vigorous vessel transport in csk1 indicate that CSK1 functions as a negative regulator of SCW biosynthesis.Through observation of green fluorescent protein-tagged CSK1 in rice protoplasts and stable transgenic plants,we found that CSK1 is localized in the nucleus and cytoplasm adjacent to the plasma membrane.Biochemical and molecular assays demonstrated that CSK1 phosphorylates VASCULAR-RELATED NAC-DOMAIN 6(VND6),a master SCW-associated transcription factor,in the nucleus,which reduces the transcription of a suite of SCW-related genes,thereby attenuating SCW accumulation.Consistently,genetic analyses show that CSK1 functions upstream of VND6 in regulating SCW formation.Interestingly,our physiological analyses revealed that CSK1 and VND6 are involved in abscisic acid-mediated regulation of cell growth and SCW deposition.Taken together,these results indicate that the CSK1-VND6 module is an important component of the SCW biosynthesis machinery,which coordinates SCW accumulation and adaptive growth in rice.Our study not only identifies a new regulator of SCW biosynthesis but also reveals a fine-tuned mechanism for precise control of SCW deposition,offering tools for rationally tailoring agronomic traits.展开更多
Receptor-like kinases(RLKs)are the most numerous signal transduction components in plants and play important roles in determining how different plants adapt to their ecological environments.Research on RLKs has focuse...Receptor-like kinases(RLKs)are the most numerous signal transduction components in plants and play important roles in determining how different plants adapt to their ecological environments.Research on RLKs has focused mainly on a small number of typical RLK members in a few model plants.There is an urgent need to study the composition,distribution,and evolution of RLKs at the holistic level to increase our understanding of how RLKs assist in the ecological adaptations of different plant species.In this study,we collected the genome assemblies of 528 plant species and constructed an RLK dataset.Using this dataset,we identified and characterized 524948 RLK family members.Each member underwent systematic topological classification and was assigned a gene ID based on a unified nomenclature system.Furthermore,we identified two novel extracellular domains in some RLKs,designated Xiao and Xiang.Evolutionary analysis of the RLK family revealed that the RLCK-XVII and RLCK-XII-2 classes were present exclusively in dicots,suggesting that diversification of RLKs between monocots and dicots may have led to differences in downstream cytoplasmic responses.We also used an interaction proteome to help empower data mining for inference of new RLK functions from a global perspective,with the ultimate goal of understanding how RLKs shape the adaptation of different plants to the environments/ecosystems.The assembled RLK dataset,together with annotations and analytical tools,forms an integrated foundation of multiomics data that is publicly accessible via the metaRLK web portal(http://metaRLK.biocloud.top).展开更多
Plants need to fine-tune defense responses to maintain a robust but flexible host barrier to various pathogens.Helix-loop-helix/basic helix-loop-helix(HLH/bHLH)complexes play important roles in fine-tuning plant devel...Plants need to fine-tune defense responses to maintain a robust but flexible host barrier to various pathogens.Helix-loop-helix/basic helix-loop-helix(HLH/bHLH)complexes play important roles in fine-tuning plant development.However,the function of these genes in plant immunity and how they are regulated remain obscure.Here,we identified an atypical bHLH transcription factor,Oryza sativa(Os)HLH46,that interacts with rice receptor-like cytoplasmic kinase(RLCK)Os BRASSINOSTEROID-SIGNALING KINASE1-2(OsBSK1-2),which plays a key role in rice blast resistance.OsBSK1-2 stabilized OsHLH46 both in vivo and in vitro.In addition,OsHLH46 positively regulates rice blast resistance,which depends on OsBSK1-2.OsHLH46 has no transcriptional activation activity and interacts with a typical bHLH protein,OsbHLH6,which negatively regulates rice blast resistance.OsbHLH6 binds to the promoter of OsWRKY45 and inhibits its expression,while OsHLH46 suppresses the function of OsbHLH6 by blocking its DNA binding and transcriptional inhibition of OsWRKY45.Consistent with these findings,OsWRKY45 was up-regulated in OsHLH46-overexpressing plants.In addition,the oshlh46 mutant overexpressing OsbHLH6 is more susceptible to Magnaporthe oryzae than is the wild type,suggesting that OsHLH46 suppresses OsbHLH6-mediated rice blast resistance.Our results not only demonstrated that OsBSK1-2 regulates rice blast resistance via the OsHLH46/OsbHLH6 complex,but also uncovered a new mechanism for plants to fine-tune plant immunity by regulating the HLH/bHLH complex via RLCKs.展开更多
Mitogen-activated protein kinase(MAPK)activation is one of the significant immune events that respond to pathogens in plants.A MAPK cascade often contains a MAPK kinase kinase(MAPKKK),a MAPK kinase(MAPKK/MKK),and a MA...Mitogen-activated protein kinase(MAPK)activation is one of the significant immune events that respond to pathogens in plants.A MAPK cascade often contains a MAPK kinase kinase(MAPKKK),a MAPK kinase(MAPKK/MKK),and a MAPK.The well-characterized MAPK cascade,to date,is the MAPKKK3/4/5-MKK4/5-MPK3/6 module.Soybean cyst nematodes(SCN)is one of the most devastating soybean pathogens.However,the early immune components contributing to soybean resistance to SCN and the role of the MAPK cascade in the soybean-SCN interaction remain unclear.A recent study published in Plant Cell discovered that GmMPK3/6 phosphorylates a receptor-like cytoplasmic kinase(RLCK),CDG1-LIKE1(GmCDL1),and maintains the stability of GmCDL1 in soybean.Remarkably,GmCDL1 enhances GmMPK3/6 activation and resistance to SCN by phosphorylating GmMAPKKK5 and activating the GmMAPKKK5-GmMKK4-GmMPK3/6 cascade.In addition,two L-type lectin receptor kinases(LecRKs),GmLecRK02g and GmLecRK08g,are involved in the GmCDL1 function after the perception of SCN.taken together,this study not only discovers a complete early immune pathway that responds to SCN infection in soybean,but also reveals a molecular mechanism by which plants maintain the activation of the MAPK cascade and resistance.展开更多
Plants employ a highly effective surveillance system to detect potential pathogens, which is critical for the success of land plants in an environment surrounded by numerous microbes. Recent efforts have led to the id...Plants employ a highly effective surveillance system to detect potential pathogens, which is critical for the success of land plants in an environment surrounded by numerous microbes. Recent efforts have led to the identification of a number of immune receptors and components of immune receptor complexes. It is now clear that receptor-like kinases （RLKs） and receptor-like proteins （RLPs） are key pattern-recognition receptors （PRRs） for microbe- and plant-derived molecular patterns that are associated with pathogen invasion. RLKs and RLPs involved in immune signaling belong to large gene families in plants and have undergone lineage specific expansion. Molecular evolution and population studies on phytopathogenic molecular signatures and their receptors have provided crucial insight into the co-evolution between plants and pathogens.展开更多
Conserved pathogen-associated molecular patterns （PAMPs）, such as chitin, are perceived by pattem recognition receptors （PRRs） located at the host cell surface and trigger rapid activation of mitogen- activated pr...Conserved pathogen-associated molecular patterns （PAMPs）, such as chitin, are perceived by pattem recognition receptors （PRRs） located at the host cell surface and trigger rapid activation of mitogen- activated protein kinase （MAPK） cascades, which are required for plant resistance to pathogens. However, the direct links from PAMP perception to MAPK activation in plants remain largely unknown. In this study, we found that the PRR-associated receptor-like cytoplasmic kinase Oryza sativa RLCK185 transmits immune signaling from the PAMP receptor OsCERK1 to an MAPK signaling cascade through interaction with an MAPK kinase kinase, OsMAPKKKε, which is the initial kinase of the MAPK cascade. OsRLCK185 interacts with and phosphorylates the C-terminal regulatory domain of OsMAPKKKε. Coexpression of phosphomi- metic OsR LCK185 and OsMAPKKKε activates MAPK3/6 phosphorylation in Nicotiana benthamiana leaves. Moreover, OsMAPKKKε interacts with and phosphorylates OsMKK4, a key MAPK kinase that transduces the chitin signal. Overexpression of OsMAPKKKε increases chitin-induced MAPK3/6 activation, whereas OsMAPKKKε knockdown compromises chitin-induced MAPK3/6 activation and resistance to rice blast fungus. Taken together, our results suggest the existence of a phospho-signaling pathway from cell surface chitin perception to intraceilular activation of an MAPK cascade in rice.展开更多
Plants utilize intracellular nucleotide-binding leucine-rich repeat domain-containing receptors (NLRs) to recognize pathogen effectors and induce a robust defense response named effector-triggered immunity (ETI). The ...Plants utilize intracellular nucleotide-binding leucine-rich repeat domain-containing receptors (NLRs) to recognize pathogen effectors and induce a robust defense response named effector-triggered immunity (ETI). The Arabidopsis NLR protein HOPZ-ACTIVATED RESISTANCE 1 (ZAR1) forms a precomplex with HOPZ-ETI-DEFICIENT 1 (ZED1),a receptor-like cytoplasmic kinase (RLCK) XII-2 subfamily member, to recognize the Pseudomonas syringae effector HopZ1 a. We previously described a dominant mutant of Arabi-dopsis ZED1, zed1-D, which displays temperature-sensitive autoimmunity in a ZAR1-dependent manner. Here, we report that the RLCKs SUPPRESSOR OF ZED1-D1 (SZE1) and SZE2 associate with the ZAR1-ZED1 complex and are required for the ZED7-D-activated autoimmune response and HopZ1a-triggered immunity. We show that SZE1 but not SZE2 has autophosphorylation activity, and that the N-terminal myristoylation of both SZE1 and SZE2 is critical for their plasma membrane localization and ZED1-D-activated autoimmunity. Furthermore, we demonstrate that SZE1 and SZE2 both interact with ZAR1 to form ja functional complex and are required for resistance against P. syringae pv. tomato DC3000 ex-pressing HopZIa. We also provide evidence that SZE1 and SZE2 interact with HopZ1a and function together with ZED1 to change the intramolecular interactions of ZAR1, leading to its activation. Taken together, our re-sults reveal SZE1 and SZE2 as critical signaling components of HopZ1a-triggered immunity.展开更多
基金supported by the Biological Breeding-National Science and Technology Major Project(2023ZD0407105)the National Natural Science Foundation of China(32272041,U21A20207)+4 种基金the National Key Research and Development Program of China(2023YFF1002400)the Innovative Project of Hubei Hongshan Laboratory(2022hszd015)the Natural Science Foundation of Hubei Province(2024AFB714,2023AFA095,2022CFA024)the Earmarked Fund for China Agriculture Research System(CARS-01)the Fundamental Research Funds for the Central Universities(2662025SKPY007).
文摘Drought stress severely limits rice productivity.Understanding of drought-response mechanisms in rice is essential for developing climate-resilient varieties.While cysteine-rich receptor-like kinases(CRKs)are primarily implicated in plant development and immunity,their role in drought response remains poorly understood.In this study,we identified a CRK,OsCRK14,as a key positive regulator of drought resistance in rice.We demonstrated that plasma membrane-localized OsCRK14 phosphorylates the receptor-like cytoplasmic kinase OsRLCK57 under drought stress,leading to activate a mitogen-activated protein kinase(MAPK)cascade(OsMKKK10-OsMKK4-OsMPK6).Activated OsMPK6 directly phosphorylates the abscisic acid-responsive transcription factor OsbZIP66 at conserved Serine-Proline/Threonine-Proline motifs,enhancing its stability and promoting drought-responsive gene expression.Furthermore,we found that natural variations in the OsCRK14 promoter influence its transcript levels due to the altered OsMYB72 binding affinities,which are correlated with drought-resistance differences among rice varieties.Collectively,our study discovers a novel CRK-RLCK-MAPK-bZIP signaling pathway that connects membrane signal sensing to transcriptional regulation in drought response,providing both mechanistic insights and genetic resources for breeding drought-resistant rice.
文摘[目的]对拟南芥类受体胞质激酶RBK2(ROP binding protein kinases 2)的结构、分子进化和基因表达等进行预测分析。[方法]利用生物信息学在线相关数据库和分析软件对目的蛋白的基本理化性质、二级及三级结构、同源性、基因表达、蛋白定位、相互作用蛋白进行分析预测。[结果]拟南芥类受体胞质激酶RBK2是一个亲水性不稳定蛋白,主要构成原件为α螺旋及β片状折叠,进化树构建及多序列比对显示其与琴叶拟南芥中名为激酶家族蛋白的蛋白进化距离最近。主要存在于细胞质和细胞核中,其编码基因在成熟花粉中强烈表达,且RBK2与PP2C家族蛋白有较强的相互作用。[结论]拟南芥RBK2很可能通过参与信号转导途径在植物种子萌发、花粉成熟及细胞分裂等方面发挥重要作用。
基金supported by NSFC grants(31991203,32130032)the National Key Research and Development Program of China(2022YFF 1003500)+1 种基金the CAS Project for Young Scientists in Basic Research(no.YSBR-078)the Strategic Priority Research Program of the Chinese Academy of Science(XDA24020306)。
文摘In angiosperms,the pollen tube enters the receptive synergid cell,where it ruptures to release its cytoplasm along with two sperm cells.This interaction is complex,and the exact signal transducers that trigger the bursting of pollen tubes are not well understood.In this study,we identify three homologous receptor-like cytoplasmic kinases(RLCKs)expressed in pollen tubes of Arabidopsis,Delayed Burst 1/2/3(DEB1/2/3),which play a crucial role in this process.These genes produce proteins localized on the plasma membrane,and their knockout causes delayed pollen tube burst and entrance of additional pollen tubes into the embryo sac due to fertilization recovery.We show that DEBs interact with the Ca^(2+)pump ACA9,influencing the dynamics of cytoplasmic Ca^(2+)in pollen tubes through phosphorylation.These results highlight the importance of DEBs as key signal transducers and the critical function of the DEB-ACA9 axis in timely pollen tube burst in synergids.
文摘Receptor-like cytoplasmic kinases （RLCKs） in plants belong to the super family of receptor-like kinases （RLKs）. These proteins show homology to RLKs in kinase domain but lack the transmembrane domain. Some of the functionally characterized RLCKs from plants have been shown to play roles in development and stress responses. Previously, 149 and 187 RLCK encoding genes were identified from Arabidopsis and rice, respectively. By using HMM-based domain structure and phylogenetic relationships, we have identified 379 OsRLCKs from rice. OsRLCKs are distributed on all 12 chromosomes of rice and some members are located on duplicated chromosomal segments. Several OsRLCKs probably also undergo alternative splicing, some having evidence only in the form of gene models. To understand their possible functions, expression patterns during landmark stages of vegetative and reproductive development as well as abiotic and biotic stress using microarray and MPSS-based data were analyzed. Real-time PCR-based expression profiling for a selected few genes confirmed the outcome of microarray analysis. Differential expression patterns observed for majority of OsRLCKs during development and stress suggest their involvement in diverse functions in rice. Majority of the stress-responsive OsRLCKs were also found to be localized within mapped regions of abiotic stress QTLs. Outcome of this study would help in selecting organ/development stage specific OsRLCK genes/targets for functional validation studies.
基金supported by the National Nature Science Foundation of China(NSFC,32030077)to Y.Z.CAS project for young scientists in basic research(YSBR-078)to B.Z.+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(grant no.XDA24010102)to Y.Z.Youth Innovation Promotion Association CAS(Y202030)to B.Z.the State Key Laboratory of Plant Genomics to Y.Z.
文摘The orderly deposition of secondary cell wall(SCW)in plants is implicated in various biological programs and is precisely controlled.Although many positive and negative regulators of SCW have been documented,the molecular mechanisms underlying SCW formation coordinated with distinct cellular physiological processes during plant adaptive growth remain largely unclear.Here,we report the identification of Cellulose Synthase co-expressed Kinase1(CSK1),which encodes a receptor-like cytoplasmic kinase,as a negative regulator of SCW formation and its signaling cascade in rice.Transcriptome deep sequencing of developing internodes and genome-wide co-expression assays revealed that CSK1 is co-expressed with cellulose synthase genes and is responsive to various stress stimuli.The increased SCW thickness and vigorous vessel transport in csk1 indicate that CSK1 functions as a negative regulator of SCW biosynthesis.Through observation of green fluorescent protein-tagged CSK1 in rice protoplasts and stable transgenic plants,we found that CSK1 is localized in the nucleus and cytoplasm adjacent to the plasma membrane.Biochemical and molecular assays demonstrated that CSK1 phosphorylates VASCULAR-RELATED NAC-DOMAIN 6(VND6),a master SCW-associated transcription factor,in the nucleus,which reduces the transcription of a suite of SCW-related genes,thereby attenuating SCW accumulation.Consistently,genetic analyses show that CSK1 functions upstream of VND6 in regulating SCW formation.Interestingly,our physiological analyses revealed that CSK1 and VND6 are involved in abscisic acid-mediated regulation of cell growth and SCW deposition.Taken together,these results indicate that the CSK1-VND6 module is an important component of the SCW biosynthesis machinery,which coordinates SCW accumulation and adaptive growth in rice.Our study not only identifies a new regulator of SCW biosynthesis but also reveals a fine-tuned mechanism for precise control of SCW deposition,offering tools for rationally tailoring agronomic traits.
基金supported by startup funds provided by Hunan Universitya database development fund provided by Suzhou Tributary Biologics Co.Ltd.,+2 种基金grants supported by the National Key R&D Program of China(2023YFD1401100)the Natural Science Foundation of China(32070769,32370757,and 32201712)the Science and Technology Innovation Program of Hunan Province(2021JJ10015,2021JJ30101,2023JJ40131,and 2023ZJ1080).
文摘Receptor-like kinases(RLKs)are the most numerous signal transduction components in plants and play important roles in determining how different plants adapt to their ecological environments.Research on RLKs has focused mainly on a small number of typical RLK members in a few model plants.There is an urgent need to study the composition,distribution,and evolution of RLKs at the holistic level to increase our understanding of how RLKs assist in the ecological adaptations of different plant species.In this study,we collected the genome assemblies of 528 plant species and constructed an RLK dataset.Using this dataset,we identified and characterized 524948 RLK family members.Each member underwent systematic topological classification and was assigned a gene ID based on a unified nomenclature system.Furthermore,we identified two novel extracellular domains in some RLKs,designated Xiao and Xiang.Evolutionary analysis of the RLK family revealed that the RLCK-XVII and RLCK-XII-2 classes were present exclusively in dicots,suggesting that diversification of RLKs between monocots and dicots may have led to differences in downstream cytoplasmic responses.We also used an interaction proteome to help empower data mining for inference of new RLK functions from a global perspective,with the ultimate goal of understanding how RLKs shape the adaptation of different plants to the environments/ecosystems.The assembled RLK dataset,together with annotations and analytical tools,forms an integrated foundation of multiomics data that is publicly accessible via the metaRLK web portal(http://metaRLK.biocloud.top).
基金supported by National Key Research and Development Program of China (2022YFF1001500)Guiding Project of Fujian Science and Technology Plan(2022N0005)
文摘Plants need to fine-tune defense responses to maintain a robust but flexible host barrier to various pathogens.Helix-loop-helix/basic helix-loop-helix(HLH/bHLH)complexes play important roles in fine-tuning plant development.However,the function of these genes in plant immunity and how they are regulated remain obscure.Here,we identified an atypical bHLH transcription factor,Oryza sativa(Os)HLH46,that interacts with rice receptor-like cytoplasmic kinase(RLCK)Os BRASSINOSTEROID-SIGNALING KINASE1-2(OsBSK1-2),which plays a key role in rice blast resistance.OsBSK1-2 stabilized OsHLH46 both in vivo and in vitro.In addition,OsHLH46 positively regulates rice blast resistance,which depends on OsBSK1-2.OsHLH46 has no transcriptional activation activity and interacts with a typical bHLH protein,OsbHLH6,which negatively regulates rice blast resistance.OsbHLH6 binds to the promoter of OsWRKY45 and inhibits its expression,while OsHLH46 suppresses the function of OsbHLH6 by blocking its DNA binding and transcriptional inhibition of OsWRKY45.Consistent with these findings,OsWRKY45 was up-regulated in OsHLH46-overexpressing plants.In addition,the oshlh46 mutant overexpressing OsbHLH6 is more susceptible to Magnaporthe oryzae than is the wild type,suggesting that OsHLH46 suppresses OsbHLH6-mediated rice blast resistance.Our results not only demonstrated that OsBSK1-2 regulates rice blast resistance via the OsHLH46/OsbHLH6 complex,but also uncovered a new mechanism for plants to fine-tune plant immunity by regulating the HLH/bHLH complex via RLCKs.
基金supported by the Science and Technology Research Program of Chongqing Municipal Education Commission(Grant No.KJQN202201225 to L.R.)the Open Fund of Fujian Provincial Key Laboratory of Eco-Industrial Green Technology(Grant No.WYKF-EIGT2022-6 to L.R.)the National Natural Science Foundation of China(Grant No.32370302 to W.W.).
文摘Mitogen-activated protein kinase(MAPK)activation is one of the significant immune events that respond to pathogens in plants.A MAPK cascade often contains a MAPK kinase kinase(MAPKKK),a MAPK kinase(MAPKK/MKK),and a MAPK.The well-characterized MAPK cascade,to date,is the MAPKKK3/4/5-MKK4/5-MPK3/6 module.Soybean cyst nematodes(SCN)is one of the most devastating soybean pathogens.However,the early immune components contributing to soybean resistance to SCN and the role of the MAPK cascade in the soybean-SCN interaction remain unclear.A recent study published in Plant Cell discovered that GmMPK3/6 phosphorylates a receptor-like cytoplasmic kinase(RLCK),CDG1-LIKE1(GmCDL1),and maintains the stability of GmCDL1 in soybean.Remarkably,GmCDL1 enhances GmMPK3/6 activation and resistance to SCN by phosphorylating GmMAPKKK5 and activating the GmMAPKKK5-GmMKK4-GmMPK3/6 cascade.In addition,two L-type lectin receptor kinases(LecRKs),GmLecRK02g and GmLecRK08g,are involved in the GmCDL1 function after the perception of SCN.taken together,this study not only discovers a complete early immune pathway that responds to SCN infection in soybean,but also reveals a molecular mechanism by which plants maintain the activation of the MAPK cascade and resistance.
基金supported by grants from Chinese Natural Science Foundation (31230007)Chinese Ministry of Science and Technology (2011CB1007002011CB100702) to J.M.Z
文摘Plants employ a highly effective surveillance system to detect potential pathogens, which is critical for the success of land plants in an environment surrounded by numerous microbes. Recent efforts have led to the identification of a number of immune receptors and components of immune receptor complexes. It is now clear that receptor-like kinases （RLKs） and receptor-like proteins （RLPs） are key pattern-recognition receptors （PRRs） for microbe- and plant-derived molecular patterns that are associated with pathogen invasion. RLKs and RLPs involved in immune signaling belong to large gene families in plants and have undergone lineage specific expansion. Molecular evolution and population studies on phytopathogenic molecular signatures and their receptors have provided crucial insight into the co-evolution between plants and pathogens.
文摘Conserved pathogen-associated molecular patterns （PAMPs）, such as chitin, are perceived by pattem recognition receptors （PRRs） located at the host cell surface and trigger rapid activation of mitogen- activated protein kinase （MAPK） cascades, which are required for plant resistance to pathogens. However, the direct links from PAMP perception to MAPK activation in plants remain largely unknown. In this study, we found that the PRR-associated receptor-like cytoplasmic kinase Oryza sativa RLCK185 transmits immune signaling from the PAMP receptor OsCERK1 to an MAPK signaling cascade through interaction with an MAPK kinase kinase, OsMAPKKKε, which is the initial kinase of the MAPK cascade. OsRLCK185 interacts with and phosphorylates the C-terminal regulatory domain of OsMAPKKKε. Coexpression of phosphomi- metic OsR LCK185 and OsMAPKKKε activates MAPK3/6 phosphorylation in Nicotiana benthamiana leaves. Moreover, OsMAPKKKε interacts with and phosphorylates OsMKK4, a key MAPK kinase that transduces the chitin signal. Overexpression of OsMAPKKKε increases chitin-induced MAPK3/6 activation, whereas OsMAPKKKε knockdown compromises chitin-induced MAPK3/6 activation and resistance to rice blast fungus. Taken together, our results suggest the existence of a phospho-signaling pathway from cell surface chitin perception to intraceilular activation of an MAPK cascade in rice.
基金National Natural Science Foundation of China (31471160)the Strategic Priority Research Program of Chinese Academy of Sciences PCDB27030102).
文摘Plants utilize intracellular nucleotide-binding leucine-rich repeat domain-containing receptors (NLRs) to recognize pathogen effectors and induce a robust defense response named effector-triggered immunity (ETI). The Arabidopsis NLR protein HOPZ-ACTIVATED RESISTANCE 1 (ZAR1) forms a precomplex with HOPZ-ETI-DEFICIENT 1 (ZED1),a receptor-like cytoplasmic kinase (RLCK) XII-2 subfamily member, to recognize the Pseudomonas syringae effector HopZ1 a. We previously described a dominant mutant of Arabi-dopsis ZED1, zed1-D, which displays temperature-sensitive autoimmunity in a ZAR1-dependent manner. Here, we report that the RLCKs SUPPRESSOR OF ZED1-D1 (SZE1) and SZE2 associate with the ZAR1-ZED1 complex and are required for the ZED7-D-activated autoimmune response and HopZ1a-triggered immunity. We show that SZE1 but not SZE2 has autophosphorylation activity, and that the N-terminal myristoylation of both SZE1 and SZE2 is critical for their plasma membrane localization and ZED1-D-activated autoimmunity. Furthermore, we demonstrate that SZE1 and SZE2 both interact with ZAR1 to form ja functional complex and are required for resistance against P. syringae pv. tomato DC3000 ex-pressing HopZIa. We also provide evidence that SZE1 and SZE2 interact with HopZ1a and function together with ZED1 to change the intramolecular interactions of ZAR1, leading to its activation. Taken together, our re-sults reveal SZE1 and SZE2 as critical signaling components of HopZ1a-triggered immunity.
