OsCERK1-Mediated Chitin Perception and Immune Signaling Requires Receptor-like Cytoplasmic Kinase 185 to Activate an MAPK Cascade in Rice  

作　　者：Chao Wang Gang Wang Chi Zhang Pinkuan Zhu Huiling Dai Nan Yu Zuhua He Ling Xu Ertao Wang 

机构地区：[1]Department of Biology, East China Normal University, Shanghai 200241, China [2]National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, ShanghaiInstitutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China [3]College of Life and Environment Sciences, Shanghai Normal University, Shanghai 200234, China

出　　处：《Molecular Plant》2017年第4期619-633,共15页分子植物（英文版）

摘　　要：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.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.

关 键 词：plant innate immunity receptor-like cytoplasmic kinase MAPK cascade CERK1 RLCK185 MAPKKKε 

分 类 号：Q26[生物学—细胞生物学] Q255