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ARS Home » Plains Area » Lincoln, Nebraska » Wheat, Sorghum and Forage Research » Research » Publications at this Location » Publication #350139
Title: Octapartite negative-sense RNA genome of high plains wheat mosaic virus encodes dual suppressors of RNA silencing

Author
item GUPTA, ADARSH - University Of Nebraska
item HEIN, GARY - University Of Nebraska
item Graybosch, Robert
item Tatineni, Satyanarayana - Ts

Submitted to: Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/15/2018
Publication Date: 3/15/2018
Citation: Gupta, A.K., Hein, G.L., Graybosch, R.A., Tatineni, S. 2018. Octapartite negative-sense RNA genome of high plains wheat mosaic virus encodes dual suppressors of RNA silencing. Virology. 518: 152-162. https://doi.org/10.1016/j.virol.2018.02.013.
DOI: https://doi.org/10.1016/j.virol.2018.02.013

Interpretive Summary: High Plains Wheat mosaic virus (HPWMoV), the causal agent of High Plains disease of wheat and maize, is an economically important virus in the Great Plains region. Recently, the genome of HPWMoV was characterized as an octapartite negative-sense RNA genome encoding eight proteins, one per genomic RNA segment. However, functions of HPWMoV-encoded proteins are not known. Determining functions of virus-encoded proteins will facilitate development of effective disease management strategies. In this study, proteins encoded by HPWMoV were examined for the suppression of RNA silencing activity, and found that RNA 7 and 8 encoded P7 and P8 proteins, respectively, possess such activity. This research revealed that the P7 and P8 genes as primary targets for developing future molecular-based methods for managing High Plains disease. Additionally, the P7 and P8 proteins can be used to unravel the mechanisms of host RNA silencing in wheat, and provide a novel route to attain consistent high-level expression of transgenes in monocotyledonous plants as many biotechnological applications are impaired by the host defense mechanism (RNA silencing).

Technical 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 ('P1) 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.