A Bunyavirus-Inducible Ubiquitin Ligase Targets RNA Polymerase IV for Degradation during Viral Pathogenesis in Rice  

作　　者：Chao Zhang Ying Wei Le Xu Kang-Cheng Wu Liang Yang Chao-Nan Shi Guo-Yi Yang Dong Chen Fei-Fei Yu Qi Xie Shou-Wei Ding Jian-Guo Wu 

机构地区：[1]Vector-borne Virus Research Center,Key Laboratory of Plant Virology of Fujian Province,Institute of Plant Virology,College of Plant Protection,Fujian Agriculture and Forestry University,Fuzhou 350002,China [2]Center for Plant Biology,Tsinghua-Peking Center for Life Sciences,College of Life Sciences,Tsinghua University,Beijing 100084,China [3]State Key Laboratory of Plant Genomics,National Center for Plant Gene Research,Institute of Genetics and Developmental Biology,Chinese Academy of Sciences,Beijing 100101,China [4]Department of Microbiology and Plant Pathology and Center for Plant Cell Biology,Institute for Integrative Genome Biology,University of California,Riverside,CA,92521,USA

出　　处：《Molecular Plant》2020年第6期836-850,共15页分子植物（英文版）

基　　金：This work was supported by the National Natural Science Foundation of China(no.31772128,31722045,U1905203,and 31701757);the Fok Ying Tung Education Foundation(161024).

摘　　要：The ubiquitin-proteasome system(UPS)is an important post-translational regulatory mechanism that controls many cellular functions in eukaryotes.Here,we show that stable expression of P3 protein encoded by Rice grassy stunt virus(RGSV),a negative-strand RNA virus in the Bunyavirales,causes developmental abnormities similar to the disease symptoms caused by RGSV,such as dwarfing and excess tillering,in transgenic rice plants.We found that both transgenic expression of P3 and RGSV infection induce ubiquitination and UPS-dependent degradation of rice NUCLEAR RNA POLYMERASE D1a(OsNRPD1a),one of two orthologs of the largest subunit of plant-specific RNA polymerase IV(Pol IV),which is required for RNA-directed DNA methylation(RdDM).Furthermore,we identified a P3-inducible U-box type E3 ubiquitin ligase,designated as P3-inducible protein 1(P3IP1),which interacts with OsNRPD1a and mediates its ubiquitination and UPS-dependent degradation in vitro and in vivo.Notably,both knockdown of OsNRPD1 and overexpression of P3IP1 in rice plants induced developmental phenotypes similar to RGSV disease symptomss.Taken together,our findings reveal a novel virulence mechanism whereby plant pathogens target host RNA Pol IV for UPS-dependent degradation to induce disease symptoms.Our study also identified an E3 ubiquitin ligase,which targets the RdDM compotent NRPD1 for UPS-mediated degradation in rice.

关 键 词：ubiquitin-proteasome system NRPD1 Rice grassy stunt virus E3 ligase 

分 类 号：S511[农业科学—作物学]