Rice blast disease caused by Magnaporthe oryzae poses a serious threat to rice security worldwide.This filamentous pathogen modulates rice defense responses by secreting effectors to facilitate infection.The phytohorm...Rice blast disease caused by Magnaporthe oryzae poses a serious threat to rice security worldwide.This filamentous pathogen modulates rice defense responses by secreting effectors to facilitate infection.The phytohormone jasmonic acid(JA)plays crucial roles in the response to rice blast fungus.However,how M.oryzae disrupts JA-mediated resistance in rice is not well understood.In this study,we identify a new effector,a chloroplast-targeting protein(MoCHT1),from M.oryzae.Knocking out MoCHT1 decreases virulence,whereas heterologous expression of MoCHT1 in rice compromises disease resistance.MoCHT1 interacts with a rice LESION AND LAMINA BENDING(OsLLB)protein,a negative regulator of JA biosynthesis in the chloroplast.Loss-of-function of Os LLB leads to increased JA accumulation,thereby improving resistance to rice blast.The interaction between MoCHT1 and OsLLB results in the inhibition of OsLLB degradation,consequently reducing JA accumulation,thereby impairing JA content and decreasing plant disease resistance.Overall,this study reveals the molecular mechanism by which M.oryzae utilizes MoCHT1 to subvert rice JA signaling,broadening our understanding of how pathogens circumvent host immune responses by manipulating plant defense hormone biosynthesis.展开更多
Magnaporthe oryzae(M.oryzae)is a devastating hemibiotrophic pathogen.Its biotrophic invasive hyphae(IH)are enclosed in the extrainvasive hyphal membrane produced by plant cells,thus generating a front line of the batt...Magnaporthe oryzae(M.oryzae)is a devastating hemibiotrophic pathogen.Its biotrophic invasive hyphae(IH)are enclosed in the extrainvasive hyphal membrane produced by plant cells,thus generating a front line of the battlefield between the pathogen and the host plants.In plants,defense-related complexes such as proteins,callose-rich materials and vesicles,are directionally secreted to this interface to confer defense responses,but the underlying molecular mechanism is poorly understood.In this study,we found that a Myosin gene,Myosin A1(OsMYA1),contributed to rice defense.The OsMYA1 knockout mutant exhibited decreased resistance to M.oryzae infection.OsMYA1 localizes to the actin cytoskeleton and surrounds the IH of M.oryzae.OsMYA1 interacts with an exocyst subunit,OsExo70H1,and regulates its accumulation at the plasma membrane(PM)and pathogen–plant interface.Furthermore,OsExo70H1 interacted with the rice syntaxin of the plants121 protein(OsSyp121),and the distribution of OsSyp121 to the PM or the pathogen–plant interface was disrupted in both the OsMYA1 and OsExo70H1 mutants.Overall,these results not only reveal a new function of OsMYA1 in rice blast resistance,but also uncover a molecular mechanism by which plants regulate defense against M.oryzae by OsMYA1-initiated vesicle secretory pathway,which originates from the actin cytoskeleton to the PM.展开更多
The dynamic assembly of the actin cytoskeleton is vital for Magnaporthe oryzae development and host infection.The actin-related protein MoFim1 is a key factor for organizing the M.oryzae actin cytoskeleton.Currently,h...The dynamic assembly of the actin cytoskeleton is vital for Magnaporthe oryzae development and host infection.The actin-related protein MoFim1 is a key factor for organizing the M.oryzae actin cytoskeleton.Currently,how MoFim1 is regulated in M.oryzae to precisely rearrange the actin cytoskeleton is unclear.In this study,we found that MoFim1 associates with the M.oryzae mitogen-activated protein(MAP)kinase Pmk1 to regulate actin assembly.MoFim1 directly interacted with Pmk1,and the phosphorylation level of MoFim1 was decreased inΔpmk1,which led to a change in the subcellular distribution of MoFim1 in the hyphae ofΔpmk1.Moreover,the actin cytoskeleton was aberrantly organized at the hyphal tip in theΔpmk1,which was similar to what was observed in theΔmofim1 during hyphal growth.Furthermore,phosphorylation analysis revealed that Pmk1 could phosphorylate MoFim1 at serine 94.Loss of phosphorylation of MoFim1 at serine 94 decreased actin bundling activity.Additionally,the expression of the site mutant of MoFim1 S94D(in which serine 94 was replaced with aspartate to mimic phosphorylation)inΔpmk1 could reverse the defects in actin organization and hyphal growth inΔpmk1.It also partially rescues the formation of appressorium failure inΔpmk1.Taken together,these findings suggest a regulatory mechanism in which Pmk1 phosphorylates MoFim1 to regulate the assembly of the actin cytoskeleton during hyphal development and pathogenesis.展开更多
基金funded by the Biological Breeding-National Science and Technology Major Projects(2023ZD04070)the National Natural Science Foundation of China(31970284,31900385)+1 种基金the Fujian Provincial Science and Technology Key Project(2022NZ030014)the Natural Science Foundation of Fujian Province,China(2023J01483,2022J01616)。
文摘Rice blast disease caused by Magnaporthe oryzae poses a serious threat to rice security worldwide.This filamentous pathogen modulates rice defense responses by secreting effectors to facilitate infection.The phytohormone jasmonic acid(JA)plays crucial roles in the response to rice blast fungus.However,how M.oryzae disrupts JA-mediated resistance in rice is not well understood.In this study,we identify a new effector,a chloroplast-targeting protein(MoCHT1),from M.oryzae.Knocking out MoCHT1 decreases virulence,whereas heterologous expression of MoCHT1 in rice compromises disease resistance.MoCHT1 interacts with a rice LESION AND LAMINA BENDING(OsLLB)protein,a negative regulator of JA biosynthesis in the chloroplast.Loss-of-function of Os LLB leads to increased JA accumulation,thereby improving resistance to rice blast.The interaction between MoCHT1 and OsLLB results in the inhibition of OsLLB degradation,consequently reducing JA accumulation,thereby impairing JA content and decreasing plant disease resistance.Overall,this study reveals the molecular mechanism by which M.oryzae utilizes MoCHT1 to subvert rice JA signaling,broadening our understanding of how pathogens circumvent host immune responses by manipulating plant defense hormone biosynthesis.
基金funded by the National Key Research and Development Program of China (2022YFF1001500)the National Natural Science Foundation of China (grant numbers 31970284,31900385)+2 种基金the Natural Science Foundation of Fujian Province,China (2023J01483, 2022J01616)the Distinguished Young Scientists Fund of Fujian Agriculture and Forestry University of China (xjq202121)the Fujian Provincial Science and Technology Key Project (2022NZ030014)
文摘Magnaporthe oryzae(M.oryzae)is a devastating hemibiotrophic pathogen.Its biotrophic invasive hyphae(IH)are enclosed in the extrainvasive hyphal membrane produced by plant cells,thus generating a front line of the battlefield between the pathogen and the host plants.In plants,defense-related complexes such as proteins,callose-rich materials and vesicles,are directionally secreted to this interface to confer defense responses,but the underlying molecular mechanism is poorly understood.In this study,we found that a Myosin gene,Myosin A1(OsMYA1),contributed to rice defense.The OsMYA1 knockout mutant exhibited decreased resistance to M.oryzae infection.OsMYA1 localizes to the actin cytoskeleton and surrounds the IH of M.oryzae.OsMYA1 interacts with an exocyst subunit,OsExo70H1,and regulates its accumulation at the plasma membrane(PM)and pathogen–plant interface.Furthermore,OsExo70H1 interacted with the rice syntaxin of the plants121 protein(OsSyp121),and the distribution of OsSyp121 to the PM or the pathogen–plant interface was disrupted in both the OsMYA1 and OsExo70H1 mutants.Overall,these results not only reveal a new function of OsMYA1 in rice blast resistance,but also uncover a molecular mechanism by which plants regulate defense against M.oryzae by OsMYA1-initiated vesicle secretory pathway,which originates from the actin cytoskeleton to the PM.
基金funded by the Natural Science Foundation of Fujian Province,China(2022J01616 and 2023J01483)the Distinguished Young Scientists Fund of Fujian Agriculture and Forestry University of China(xjq202121)+1 种基金the National Natural Science Foundation of China(grant numbers.31970284,31900385)the Fujian Provincial Science and Technology Key Project(2022NZ030014).
文摘The dynamic assembly of the actin cytoskeleton is vital for Magnaporthe oryzae development and host infection.The actin-related protein MoFim1 is a key factor for organizing the M.oryzae actin cytoskeleton.Currently,how MoFim1 is regulated in M.oryzae to precisely rearrange the actin cytoskeleton is unclear.In this study,we found that MoFim1 associates with the M.oryzae mitogen-activated protein(MAP)kinase Pmk1 to regulate actin assembly.MoFim1 directly interacted with Pmk1,and the phosphorylation level of MoFim1 was decreased inΔpmk1,which led to a change in the subcellular distribution of MoFim1 in the hyphae ofΔpmk1.Moreover,the actin cytoskeleton was aberrantly organized at the hyphal tip in theΔpmk1,which was similar to what was observed in theΔmofim1 during hyphal growth.Furthermore,phosphorylation analysis revealed that Pmk1 could phosphorylate MoFim1 at serine 94.Loss of phosphorylation of MoFim1 at serine 94 decreased actin bundling activity.Additionally,the expression of the site mutant of MoFim1 S94D(in which serine 94 was replaced with aspartate to mimic phosphorylation)inΔpmk1 could reverse the defects in actin organization and hyphal growth inΔpmk1.It also partially rescues the formation of appressorium failure inΔpmk1.Taken together,these findings suggest a regulatory mechanism in which Pmk1 phosphorylates MoFim1 to regulate the assembly of the actin cytoskeleton during hyphal development and pathogenesis.
