Broad bean wilt virus causes necrotic symptoms and generates defective RNAs in Capsicum annuum

A virus was isolated from hot pepper (Capsicum annuum cv. Hyang Chon) growi ng in Korea and displaying necrotic spots or streaks on leaves and stems fo llowed by stunting and death of plants. Morphological and host range analys es of extracts from infected plants suggested that the causal agent of dise ase was a Broad bean wilt virus (BBWV), and the virus was tentatively named a Korean isolate of BBWV (BBWV-K). When the isolate was back-inoculated on to hot pepper plants, it induced symptoms similar to those of naturally inf ected hot pepper in the field. Two coat proteins (CPs) of 44 and 22 kDa, co rresponding to a large CP and a small CP, respectively, were identified fro m the virus, and both reacted specifically with polyclonal antibody to BBWV 2. The complete nucleotide sequences of RNA 1 and RNA 2 of the isolate wer e determined from cDNA clones. The deduced amino acid sequence data from th e putative proteins encoded by RNA 1 and 2 of the BBWV-K indicated a closer relationship with the isolates of BBWV 2 than BBWV 1. However, sequence co mparison of the 5' noncoding regions of the viruses differentiates BBWV-K f rom other BBWV 2 isolates. Another distinctive feature of the BBWV-K is tha t it generates defective RNAs in hot pepper exhibiting necrotic symptoms, w hich is the first report of defective RNAs in the Fabavirus genera of BBWVs .