Viral suppressors of RNA silencing in Wheat mosaic virus (WMoV)

Authors: GUPTA, A - University Of Nebraska; HEIN, G - University Of Nebraska; Graybosch, Robert; Tatineni, Satyanarayana - Ts

Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 5/7/2015
Publication Date: 7/25/2015
Publication URL: http://www.apsnet.org/meetings/Documents/2015_meeting_abstracts/aps2015abP646.htm
Citation: Gupta, A., Hein, G.L., Graybosch, R.A., Tatineni, S. 2015. Viral suppressors of RNA silencing in Wheat mosaic virus (WMoV). American Phytopathological Society Annual Meeting. 726-P.

Interpretive Summary:

Technical Abstract: RNA silencing is the most effective antiviral adaptive defense mechanism mounted in higher plants to combat viral infection and proliferation. However, viruses have developed a variety of efficient counter-defense mechanisms by suppression of RNA silencing (VSR) in order to successfully impede the host defense. Wheat mosaic virus (WMoV), the causative of High Plains disease, an economically important disease in wheat (Triticum aestivum L.) and maize (Zea mays L.), is an eriophyid-mite (Aceria tosichella Keifer) transmitted Emaravirus. It harbors an octapartite negative-sense single-stranded RNA genome with monocistronic RNA segments. In this study, we screened the WMoV genome for potential candidates with VSR activity through GFP-reporter assays by agroinfiltration. Each open reading frame of WMoV RNAs 2 to 8 was cloned into a 35S driven expression vector pCASS4 and transformed into Agrobacterium tumefaciens. Equal amounts of agrosuspensions harboring WMoV ORFs and 35S-GFP were coinfiltrated into Nicotiana benthamiana wild-type and GFP-transgenic 16c leaves. Agroinfiltrated leaves showed prolonged, albeit weak, green fluorescence in the case of ORFs 5, 7 and 8 and substantially reduced accumulation of GFP-specific siRNAs in the presence of ORFs 7 and 8. Our data suggest that WMoV encodes multiple proteins with weak VSR activity.