title: Identification of an RNA silencing suppressor from a plant double-stranded RNA virus.
abstract: RNA silencing is a mechanism which higher plants and animals have evolved to defend against viral infection in addition to regulation of gene expression for growth and development. As a counterdefense, many plant and some animal viruses studied to date encode RNA silencing suppressors (RSS) that interfere with various steps of the silencing pathway. In this study, we report the first identification of an RSS from a plant double-stranded RNA (dsRNA) virus. Pns10, encoded by S10 of Rice dwarf phytoreovirus (RDV), exhibited RSS activity in coinfiltration assays with the reporter green fluorescent protein (GFP) in transgenic Nicotiana benthamiana line 16c carrying GFP. The other gene segments of the RDV genome did not have such a function. Pns10 suppressed local and systemic silencing induced by sense RNA but did not interfere with local and systemic silencing induced by dsRNA. Expression of Pns10 also increased the expression of beta-glucuronidase in transient assays and enhanced Potato virus X pathogenicity in N. benthamiana. Collectively, our results establish Pns10 as an RSS encoded by a plant dsRNA virus and further suggest that Pns10 targets an upstream step of dsRNA formation in the RNA silencing pathway.
authors.affiliation: Peking-Yale Joint Center for Plant Molecular Genetics and Agrobiotechnology, National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing, China.
authors.forename: Xuesong
authors.initials: X
authors.lastname: Cao
authors.forename: Peng
authors.initials: P
authors.lastname: Zhou
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Zhang
authors.forename: Shifeng
authors.initials: S
authors.lastname: Zhu
authors.forename: Xuehua
authors.initials: X
authors.lastname: Zhong
authors.forename: Qi
authors.initials: Q
authors.lastname: Xiao
authors.forename: Biao
authors.initials: B
authors.lastname: Ding
authors.forename: Yi
authors.initials: Y
authors.lastname: Li
mesh_terms: D010935:Plant Diseases / Q000821:virology; D010942:Plant Viruses / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D034622:RNA Interference; D012328:RNA Viruses / Q000235:genetics* / Q000378:metabolism; D014026:Nicotiana; D017361:Viral Nonstructural Proteins / Q000378:metabolism / Q000502:physiology*
chemical_list: D017361:Viral Nonstructural Proteins