The jasmonate pathway promotes nodule symbiosis and suppresses host plant defense in Medicago truncatula  

作　　者：Da Guo Jingrui Li Peng Liu Yuzhan Wang Na Cao Xiangling Fang Tao Wang Jiangli Dong 

机构地区：[1]College of Biological Sciences,China Agricultural University,Beijing 100193,China [2]State Key Laboratory of Plant Environmental Resilience,College of Biological Sciences,China Agricultural University,Bejing 100193,China [3]State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems,College of Pastoral Agriculture Science and Technology,Lanzhou University,Lanzhou730020,China

出　　处：《Molecular Plant》2024年第8期1183-1203,共21页分子植物（英文版）

基　　金：National Natural Science Foundation of China(32370253,and 32070272);the National Key Research Development Program of China(2022YFA0912100,and 2023YFF1001400).

摘　　要：Root nodule symbiosis(RNs)between legumes and rhizobia is a major source of nitrogen in agricultural systems.Effective symbiosis requires precise regulation of plant defense responses.The role of the defense hormone jasmonic acid(JA)in the immune response has been extensively studied.Current research shows that JA can play either a positive or negative regulatory role in RNS depending on its concentration,but the molecular mechanisms remain to be elucidated.In this study,we found that inoculation with the rhizobia Sm1021 induces the JA pathway in Medicago truncatula,and blocking the JA pathway significantly reduces the number of infection threads.Mutations in the MtMYc2 gene,which encodes a JA signaling master transcription factor,significantly inhibited rhizobia infection,terminal differentiation,and symbiotic cell formation.Combining RNA sequencing and chromatin immunoprecipitation sequencing,we discovered that MtMYc2 regulates the expression of nodule-specific MtDNF2,MtNAD1,and MtSymCRK to suppress host defense,while it activates MtDNF1 expression to regulate the maturation of MtNCRs,which in turn promotes bacteroid formation.More importantly,MtMYC2 participates in symbiotic signal transduction by promoting the expression of MtiPD3.Notably,the MtMYC2-MtiPD3 transcriptional regulatory module is specifically present in legumes,and the Mtmyc2 mutants are susceptible to the infection by the pathogen Rhizoctonia solani.Collectively,these findings reveal the molecular mechanisms of how the JA pathway regulates RNS,broadening our understanding of the roles of JA in plant-microbe interactions.

关 键 词：jasmonic acid MYC2 SYMBIOSIS DEFENSE Medicago truncatula 

分 类 号：Q94[生物学—植物学]