Recombinant soybean mosaic virus is prevalent in Chinese soybean fields.

Recombinant soybean mosaic virus (SMV-R) is a novel strain that has recently been identified. SMV-R was first isolated from Chongqing, China, and exhibits different pathogenicity on soybeans and common beans compared with normal soybean mosaic virus (SMV-N). SMV-R arose from a recombination event between SMV and bean common mosaic virus (BCMV) or a BCMV-like virus. In this study, we assessed the prevalence of SMV-R in Chinese soybean fields. Polymerase chain reaction results showed that SMV-R was common (16.7-60 %) in the central and southern provinces of China, based on 206 isolates collected from across China. Furthermore, the results from three provinces suggest that SMV-R strains are present in mixed infections with other SMV strains. Additionally, the phylogenetic status of SMV-R strongly supports a previous hypothesis that watermelon mosaic virus arose from a recombination event between SMV and a BCMV-like virus.