Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/12/2013
Publication Date: 6/1/2013
Citation: Hammond, R. 2013. Evaluating the silencing suppressor activity of proteins encoded by maize rayado fino virus. Meeting Abstract. Phytopathology Vol. 103 (S2), 56. ISSN: 0031-949X.
Technical Abstract: Maize rayado fino virus (MRFV), the type member of the genus Marafivirus, family Tymoviridae, is transmitted in a persistent, circulative manner by leafhoppers of the genus Dalbulus. Symptoms of MRFV infection on leaves of its maize host are small chlorotic spots that coalesce into short stripes. The 6.3 kb genomic ssRNA encodes a 224 kDa polyprotein with replication protein motifs at the amino terminus, and two capsid proteins (CPs) with 3’ co-terminal sequences at the carboxy terminus. A putative ORF of 43 kDa with unknown function has been proposed. Silencing suppressor proteins encoded by plant viruses are diverse; it is not known if MRFV-encoded proteins possess silencing suppressor activities. Expression of the MRFV CPs in Nicotiana benthamiana using a Potato virus X (PVX)-based vector resulted in MRFV VLP accumulation and enhanced the pathogenicity of PVX. In addition, co-infiltration of agrobacteria containing GFP and MRFV CP constructs resulted in enhanced GFP fluorescence and accumulation of GFP protein, but at levels lower than observed in the presence of the silencing suppressor p19. These observations suggest that the MRFV CP may be a weak silencing suppressor. Additional MRFV proteins did not show the same silencing suppressor activity. This is the first report suggesting that marafiviruses encode silencing suppressor proteins; however their role in viral pathogenicity is not known.