Chao Zhang, Dong Chen, Guoyi Yang, Xiyuan Yu, and Jianguo Wu†, Rice Stripe Mosaic Virus–Encoded P4 Is A Weak Suppressor of Viral RNA Silencing and Is Required for Disease Symptom Development. [J] MPMI, 2020

  发布时间: 2020-05-21   信息员:   


Viral suppressors of RNA silencing (VSRs) are a cluster of viral proteins that have evolved to counteract eukaryotic antiviral RNA silencing pathways, thereby contributing to viral patho genicity. In this study, we revealed that the matrix protein P4 encoded by rice stripe mosaic virus (RSMV), which is an emerging cytoplasmic rhabdovirus, is a weak RNA silencing suppressor. By conducting yeast two-hybrid, bimolecular fluorescence complementation, and subcellular colocalization assays, we proved that P4 interacts with the rice endogenous suppressor of gene silencing 3 (OsSGS3). We also determined that P4 overexpression has no effect on OsSGS3 transcription.

However, P4 can promote the degradation of OsSGS3 via ubiquitination and autophagy. Additionally, a potato virus X– based expression system was used to confirm that P4 enhances the development of mosaic symptoms on Nicotiana benthamiana leaves by promoting hydrogen peroxide accumulation but not cell death. To verify whether P4 is a pathogenicity factor in host plants, we generated transgenic P4-overexpressing rice plants that exhibited disease-related developmental defects including decreased plant height and excessive tillering. Our data suggest that RSMV-encoded P4 serves as a weak VSR that inhibits antiviral RNA silencing by targeting OsSGS3.

Keywords: P4, RNA silencing, rice stripe mosaic virus (RSMV), Suppressor of gene silencing 3