Rice bacterial blight,caused by the pathogen Xanthomonas oryzae pv.oryzae(Xoo),poses a significant threat to rice crops.Arginine methylation,a post-translational modification of proteins,plays a pivotal role in transc...Rice bacterial blight,caused by the pathogen Xanthomonas oryzae pv.oryzae(Xoo),poses a significant threat to rice crops.Arginine methylation,a post-translational modification of proteins,plays a pivotal role in transcriptional regulation,RNA processing,and the biosynthesis of plant hormones.Previous research has established that protein arginine methyltransferases(PRMTs)significantly influence protein function through arginine methylation.Nonetheless,the specific role of PRMT5 in regulating salicylic acid(SA)biosynthesis and plant immunity has been relatively unexplored.In this study,we elucidate the role of a rice protein arginine methyltransferase,OsPRMT5,in enhancing rice resistance to Xoo infection by interacting with the SA biosynthesis enzyme phenylalanine ammonia lyase 1 in rice(OsPAL1).Our results indicate that OsPRMT5 methylates OsPAL1 at the arginine residue 75,which affects the interaction between OsPRMT5 and OsPAL1 and subsequently boosts phenylalanine ammonia lyase(PAL)enzyme activity,leading to heightened SA accumulation.Conversely,compared to OsPAL1 overexpression plants in wild-type TP309 background,OsPAL1 overexpression plants in osprmt5 knockout(KO)mutants background exhibited diminished PAL activity.Furthermore,osprmt5 ospal1 double mutants demonstrated reduced resistance to bacterial blight compared to the OsPAL1-KO group.Additionally,we discovered that the Xoo effector protein PXO_01039 undermines the interaction between OsPRMT5 and OsPAL1,thereby facilitating Xoo infection.PXO_01039 binds to OsPRMT5,preventing the formation of the OsPRMT5-OsPAL1 complex,which results in decreased PAL activity and lower SA accumulation.In conclusion,our findings unveil how OsPRMT5 modulates the methylation and enzymatic activity of OsPAL1,a crucial enzyme in SA biosynthesis,to bolster plant antibacterial defenses.展开更多
Rice ARGONAUTE2(OsAGO2)is a core component of the rice RNA-induced silencing complex(RISC),which is repressed by Magnaporthe oryzae(M.oryzae)infection.Whether and how OsAGO2-mediated gene silencing plays a role in ric...Rice ARGONAUTE2(OsAGO2)is a core component of the rice RNA-induced silencing complex(RISC),which is repressed by Magnaporthe oryzae(M.oryzae)infection.Whether and how OsAGO2-mediated gene silencing plays a role in rice blast resistance and which sRNAs participate in this process are unknown.Our results indicate that OsAGO2 is a key immune player that manipulates rice defense responses against blast disease.OsAGO2 associates with the 24-nt miR1875 and binds to the promoter region of HEXOKINASE1(OsHXK1),which causes DNA methylation and leads to gene silencing.Our multiple genetic evidence showed that,without M.oryzae infection,OsAGO2/miR1875 RISC promoted OsHXK1 promoter DNA methylation and OsHXK1 silencing;after M.oryzae infection,the reduced OsAGO2/miR1875 led to a relatively activated OsHXK1 expression.OsHXK1 acts as a positive regulator of blast disease resistance that OsHXK1-OE rice exhibited enhanced resistance,whereas Cas9-Oshxk1 rice showed reduced resistance against M.oryzae infection.OsHXK1 may function through its sugar sensor activity as glucose induced defense-related gene expression and reactive oxygen species(ROS)accumulation in Nipponbare and OsHXK1-OE but not in Cas9-Oshxk1 rice.OsAGO2 itself is delicately regulated by OsPRMT5,which senses M.oryzae infection and attenuates OsAGO2-mediated gene silencing through OsAGO2 arginine methylation.Our study reveals an OsPRMT5-OsAGO2/miR1875-OsHXK1 regulatory module that fine tunes the rice defense response to blast disease.展开更多
基金supported by the Natural Science Foundation of China (32072379) to F.L.Jiangsu Funding Program for Excellent Postdoctoral Talent (2023ZB136) to C.S.the Basal Research Fund for the Jiangsu Academy of Agricultural Sciences (ZX(23)3016, ZX(24)3014).
文摘Rice bacterial blight,caused by the pathogen Xanthomonas oryzae pv.oryzae(Xoo),poses a significant threat to rice crops.Arginine methylation,a post-translational modification of proteins,plays a pivotal role in transcriptional regulation,RNA processing,and the biosynthesis of plant hormones.Previous research has established that protein arginine methyltransferases(PRMTs)significantly influence protein function through arginine methylation.Nonetheless,the specific role of PRMT5 in regulating salicylic acid(SA)biosynthesis and plant immunity has been relatively unexplored.In this study,we elucidate the role of a rice protein arginine methyltransferase,OsPRMT5,in enhancing rice resistance to Xoo infection by interacting with the SA biosynthesis enzyme phenylalanine ammonia lyase 1 in rice(OsPAL1).Our results indicate that OsPRMT5 methylates OsPAL1 at the arginine residue 75,which affects the interaction between OsPRMT5 and OsPAL1 and subsequently boosts phenylalanine ammonia lyase(PAL)enzyme activity,leading to heightened SA accumulation.Conversely,compared to OsPAL1 overexpression plants in wild-type TP309 background,OsPAL1 overexpression plants in osprmt5 knockout(KO)mutants background exhibited diminished PAL activity.Furthermore,osprmt5 ospal1 double mutants demonstrated reduced resistance to bacterial blight compared to the OsPAL1-KO group.Additionally,we discovered that the Xoo effector protein PXO_01039 undermines the interaction between OsPRMT5 and OsPAL1,thereby facilitating Xoo infection.PXO_01039 binds to OsPRMT5,preventing the formation of the OsPRMT5-OsPAL1 complex,which results in decreased PAL activity and lower SA accumulation.In conclusion,our findings unveil how OsPRMT5 modulates the methylation and enzymatic activity of OsPAL1,a crucial enzyme in SA biosynthesis,to bolster plant antibacterial defenses.
基金supported by the Natural Science Foundation of China(31872040)a Jiangsu Agricultural Science and Technology Innovation Fund(CX(21)3090)to HZ+2 种基金Shandong Province Natural Science Foundation of China(ZR2019PC049)Science and Technology Program of Zaozhuang(2020NS13)National College Students Innovation and Entrepreneurship Training Program(202110904107)to PN。
文摘Rice ARGONAUTE2(OsAGO2)is a core component of the rice RNA-induced silencing complex(RISC),which is repressed by Magnaporthe oryzae(M.oryzae)infection.Whether and how OsAGO2-mediated gene silencing plays a role in rice blast resistance and which sRNAs participate in this process are unknown.Our results indicate that OsAGO2 is a key immune player that manipulates rice defense responses against blast disease.OsAGO2 associates with the 24-nt miR1875 and binds to the promoter region of HEXOKINASE1(OsHXK1),which causes DNA methylation and leads to gene silencing.Our multiple genetic evidence showed that,without M.oryzae infection,OsAGO2/miR1875 RISC promoted OsHXK1 promoter DNA methylation and OsHXK1 silencing;after M.oryzae infection,the reduced OsAGO2/miR1875 led to a relatively activated OsHXK1 expression.OsHXK1 acts as a positive regulator of blast disease resistance that OsHXK1-OE rice exhibited enhanced resistance,whereas Cas9-Oshxk1 rice showed reduced resistance against M.oryzae infection.OsHXK1 may function through its sugar sensor activity as glucose induced defense-related gene expression and reactive oxygen species(ROS)accumulation in Nipponbare and OsHXK1-OE but not in Cas9-Oshxk1 rice.OsAGO2 itself is delicately regulated by OsPRMT5,which senses M.oryzae infection and attenuates OsAGO2-mediated gene silencing through OsAGO2 arginine methylation.Our study reveals an OsPRMT5-OsAGO2/miR1875-OsHXK1 regulatory module that fine tunes the rice defense response to blast disease.
