RESUMO
Red clover necrotic mosaic virus (RCNMV; genus Dianthovirus) and Turnip rosette virus (TRoV; genus Sobemovirus) are taxonomically and ecologically distinct plant viruses. In addition, the two genera differ in the role of coat protein (CP) in cell-to-cell movement. However, both are small icosahedral viruses requiring CP for systemic movement in the host vasculature. Here, we show that the TRoV CP gene is capable of facilitating the vascular movement of a Dianthovirus. Substitution of the RCNMV CP gene with the TRoV CP gene permits movement of the resulting chimeric virus to non-inoculated leaves. RCNMV lacking a CP gene or containing a non-translatable TRoV CP gene do not move systemically. This report introduces the molecular characterization of TRoV and describes the unprecedented complementation of systemic movement function by intergenic complete substitution of a plant virus CP gene.
Assuntos
Vírus de RNA/genética , Tombusviridae/genética , Arabidopsis/virologia , Sequência de Bases , Brassica napus/virologia , Proteínas do Capsídeo/genética , Primers do DNA , Genoma Viral , Dados de Sequência Molecular , Conformação de Ácido Nucleico , Vírus de RNA/classificação , RNA Viral/química , RNA Viral/genética , Tombusviridae/classificaçãoRESUMO
Red clover necrotic mosaic virus (RCNMV) encodes N-terminally overlapping proteins of 27 and 88 kDa (p27 and p88) known to be required for replication. Green fluorescent protein (GFP) fusions were used to visualize the location of p27 and p88 within Nicotiana benthamiana cells. GFP:p27 fusions localized to the endoplasmic reticulum (ER), co-localized with ER-targeted yellow fluorescent protein and caused membrane restructuring and proliferation. Cellular fractionation of virus-inoculated N. benthamiana leaves confirmed the association of p27 with ER membranes. GFP:p88 fusions also localized to the ER and co-localized with GFP:p27. Both fusion proteins co-localize to the cortical and cytoplasmic ER and were associated with invaginations of the nuclear envelope. Independent accumulation in, and perturbation of, the ER suggests that p27 and p88 function together in the replication complex. This is the first report of a member of the Tombusviridae replicating in association with the ER.
