title: Diverse suppressors of RNA silencing enhance agroinfection by a viral replicon.
abstract: Launching the Beet yellows virus (BYV) minireplicon by agrobacterial delivery resulted in an unexpectedly low number of infected cells per inoculated leaf. This effect was due to a strong RNA silencing response in the agroinfiltrated leaves. Strikingly, ectopic co-expression of p21, a BYV RNA silencing suppressor, increased minireplicon infectivity by three orders of magnitude. Mutational analysis demonstrated that this effect correlates with suppressor activity of p21. Five diverse, heterologous viral suppressors were also active in this system, providing a useful approach for a dramatic, up to 10,000-fold, increase of the efficiency of agroinfection. The minireplicon agroinfection assay was also used to identify a new suppressor, a homolog of BYV p21, derived from Grapevine leafroll-associated virus-2. In addition, we report preliminary data on the suppressor activity of the p10 protein of Grapevine virus A and show that this protein belongs to a family of Zn-ribbon-containing proteins encoded by filamentous plant RNA viruses from three genera. The members of this family are predicted to have RNA silencing suppressor activity.
authors.affiliation: Department of Botany and Plant Pathology and Center for Gene Research and Biotechnology, Oregon State University, Corvallis, OR 97331, USA.
authors.forename: Marin
authors.initials: M
authors.lastname: Chiba
authors.forename: Jonathan C
authors.initials: JC
authors.lastname: Reed
authors.forename: Alexey I
authors.initials: AI
authors.lastname: Prokhnevsky
authors.forename: Elisabeth J
authors.initials: EJ
authors.lastname: Chapman
authors.forename: Munir
authors.initials: M
authors.lastname: Mawassi
authors.forename: Eugene V
authors.initials: EV
authors.lastname: Koonin
authors.forename: James C
authors.initials: JC
authors.lastname: Carrington
authors.forename: Valerian V
authors.initials: VV
authors.lastname: Dolja
mesh_terms: D000595:Amino Acid Sequence; D017790:Closterovirus / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*; D004279:DNA, Viral / Q000235:genetics; D008969:Molecular Sequence Data; D018515:Plant Leaves / Q000821:virology; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012093:Replicon / Q000235:genetics / Q000502:physiology*; D012231:Rhizobium / Q000235:genetics; D014026:Nicotiana / Q000821:virology*; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D004279:DNA, Viral; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins; D014764:Viral Proteins