Determination of 3′-terminal nucleotide sequence of pepper\break vein banding virus RNA and expression of its coat protein in Escherichia coli

Abstract

Pepper vein banding virus (PVBV) is an important virus infecting chilli pepper in south India. Earlier reports suggested it to be a distinct potyvirus. The nucleotide sequence of PVBV RNA from the 3'-end (3862 nt) was determined. Analysis of the nucleotide and deduced amino acid sequence revealed that it encompasses a partial open reading frame encoding the partial sequence of VPg, NIa-protease, NIb, coat protein (CP) and 3'-untranslated region (UTR). Comparison of the amino acid sequence of CP and the nucleotide sequence of 3'-UTR with those of other potyviruses confirmed an earlier observation that PVBV is a distinct member of the Potyvirus sub-group and it had significant similarity to a recently characterized virus infecting chilli pepper, chilli vein-banding mottle virus (CVbMV), from Thailand. The analysis showed that both PVBV and CVbMV might represent strains of the same virus. Further, the PVBV CP gene was overexpressed in E. coli, which assembled into potyvirus-like particles (PVLPs). The assembled particles were shown to encapsidate the CP mRNA.