title: Multiple suppressors of RNA silencing encoded by both genomic RNAs of the crinivirus, Tomato chlorosis virus.
abstract: Viruses express proteins with silencing suppression activity to counteract the RNA silencing-mediated defense response of the host. In the family Closteroviridae, examples of multiple-component RNA silencing suppression systems have been reported. To ascertain if this is a general strategy in this group of viruses, we have explored the bipartite genome of Tomato chlorosis virus (ToCV, genus Crinivirus). We have identified the RNA1-encoded p22 protein as an effective silencing suppressor by using a Agrobacterium co-infiltration assay. p22 suppressed local RNA silencing induced either by sense RNA or dsRNA very efficiently, but did not interfere with short or long-distance systemic spread of silencing. We have also demonstrated by using the heterologous vector PVX the silencing suppression activity of the RNA-2 encoded coat protein (CP) and minor coat protein (CPm). In this study, we demonstrate an even greater complexity of silencing suppressor activity for a plant virus, and for the first time we show the presence of RNA silencing suppressor genes encoded by both genomic RNA molecules of a bipartite genome in the complex family Closteroviridae.
authors.affiliation: Estación Experimental La Mayora, Consejo Superior de Investigaciones Científicas, 29760 Algarrobo-Costa, Málaga, Spain.
authors.forename: M Carmen
authors.initials: MC
authors.lastname: Cañizares
authors.forename: Jesús
authors.initials: J
authors.lastname: Navas-Castillo
authors.forename: Enrique
authors.initials: E
authors.lastname: Moriones
mesh_terms: D029383:Crinivirus / Q000235:genetics / Q000502:physiology*; D018551:Solanum lycopersicum / Q000276:immunology* / Q000821:virology; D034622:RNA Interference; D012330:RNA, Double-Stranded / Q000378:metabolism; D012367:RNA, Viral / Q000378:metabolism*; D014764:Viral Proteins / Q000235:genetics / Q000502:physiology*
chemical_list: D012330:RNA, Double-Stranded; D012367:RNA, Viral; D014764:Viral Proteins