title: Rice yellow stunt rhabdovirus protein 6 suppresses systemic RNA silencing by blocking RDR6-mediated secondary siRNA synthesis.
abstract: The P6 protein of Rice yellow stunt rhabdovirus (RYSV) is a virion structural protein that can be phosphorylated in vitro. However its exact function remains elusive. We found that P6 enhanced the virulence of Potato virus X (PVX) in Nicotiana benthamiana and N. tabacum plants, suggesting that it might function as a suppressor of RNA silencing. We examined the mechanism of P6-mediated silencing suppression by transiently expressing P6 in both N. benthamiana leaves and rice protoplasts. Our results showed that P6 could repress the production of secondary siRNAs and inhibit systemic green fluorescent protein RNA silencing but did not interfere with local RNA silencing in N. benthamiana plants or in rice protoplasts. Intriguingly, P6 and RDR6 had overlapping subcellular localization and P6 bound both rice and Arabidopsis RDR6 in vivo. Furthermore, transgenic rice plants expressing P6 showed enhanced susceptibility to infection by Rice stripe virus. Hence, we propose that P6 is part of the RYSV's counter-defense machinery against the plant RNA silencing system and plays a role mainly in affecting RDR6-mediated secondary siRNA synthesis. Our work provides a new perspective on how a plant-infecting nucleorhabdovirus may counteract host RNA silencing-mediated antiviral defense.
authors: Chinese Academy of Sciences, Beijing, China.
authors: Hongyan
authors: H
authors: Guo
authors: Xiaoguang
authors: X
authors: Song
authors: Chuanmiao
authors: C
authors: Xie
authors: Yan
authors: Y
authors: Huo
authors: Fujie
authors: F
authors: Zhang
authors: Xiaoying
authors: X
authors: Chen
authors: Yunfeng
authors: Y
authors: Geng
authors: Rongxiang
authors: R
authors: Fang
mesh_terms: D000818:Animals; D003593:Cytoplasm / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D012275:Oryza / Q000378:metabolism; D010935:Plant Diseases / Q000821:virology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D010957:Plasmids; D017863:Potexvirus / Q000472:pathogenicity; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism*; D012209:Rhabdoviridae / Q000378:metabolism*; D014026:Nicotiana / Q000821:virology; D014764:Viral Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D014774:Virulence
chemical_list: D010940:Plant Proteins; D034741:RNA, Small Interfering; D014764:Viral Proteins