Octapartite negative-sense RNA genome of High Plains wheat mosaic virus encodes two suppressors of RNA silencing

Authors

• Adarsh K. Gupta, University of Nebraska -LincolnFollow
• Gary L. Hein, University of Nebraska - LincolnFollow
• Robert A. Graybosch, USDA, Agricultural Research ServiceFollow
• Satyanarayana Tatineni, USDA, Agricultural Research ServiceFollow

Document Type

Article

Date of this Version

2018

Citation

Virology 518 (2018) 152–162

Comments

This document is a U.S. government work and is not subject to copyright in the United States.

Abstract

High Plains wheat mosaic virus (HPWMoV, genus Emaravirus; family Fimoviridae), transmitted by the wheat curl mite (Aceria tosichella Keifer), harbors a monocistronic octapartite single-stranded negative-sense RNA genome. In this study, putative proteins encoded by HPWMoV genomic RNAs 2–8 were screened for potential RNA silencing suppression activity by using a green fluorescent protein-based reporter agroinfiltration assay. We found that proteins encoded by RNAs 7 (P7) and 8 (P8) suppressed silencing induced by single- or doublestranded RNAs and efficiently suppressed the transitive pathway of RNA silencing. Additionally, a Wheat streak mosaic virus (WSMV, genus Tritimovirus; family Potyviridae) mutant lacking the suppressor of RNA silencing (ΔP1) but having either P7 or P8 from HPWMoV restored cell-to-cell and long-distance movement in wheat, thus indicating that P7 or P8 rescued silencing suppressor-deficient WSMV. Furthermore, HPWMoV P7 and P8 substantially enhanced the pathogenicity of Potato virus X in Nicotiana benthamiana. Collectively, these data demonstrate that the octapartite genome of HPWMoV encodes two suppressors of RNA silencing.