Abstract：Rice gall dwarf virus (RGDV) is a member of the genus Phytoreovirus in the family Reoviridae, which is transmitted by leafhopper Recilia dorsalis and Nephotettix cincticeps in a persistent-propagative manner. The viral genome of RGDV encodes 6 structural proteins and 6 nonstructural proteins. The structural protein P8 is a component of viral outer capsid protein, but the function of this protein in viral infection in insect vector is still unknown. Here, RNA interference (RNAi) induced by double-stranded RNA(dsRNA) synthesized in vitro was used to investigate the role of RGDV P8 protein in viral infection in the cultured cells derived from R. dorsalis. Immunofluorescence assay of RGDV infection in cultured cells after the treatment of dsRNAs from P8 gene (dsP8) howed that dsP8 did not only knock down the expression of P8, but also reduced the accumulation of RGDV in the insect vector cells. Then viral dsRNA genome and proteins were detected by SDS-PAGE and Western blot, the results indicated that the treatment of dsP8 significantly decreased the synthesis of viral dsRNA genome and the expression of P8 protein in insect vector cells. Thus, the results suggested that structural protein P8 of RGDV might play a role in viral assembly and multiplication in insect vector cells. This provides important theoretical basis for controling the spreading of rice gall dwarf disease by using RNAi technology.
