Fine Mapping and Candidate Gene Discovery at the Rsv3 Locus

Soybean mosaic virus (SMV) is the most common member of the viral genus Potyvirus to infect soybeans (Glycine max [L.] Merr.) worldwide. SMV has been traditionally controlled by the deployment of single dominant, strain specific resistance genes, referred to as Rsv genes. Rsv1 is the most widely used form of SMV resistance with nine different alleles conferring resistance only to the lower numbered less virulent strains, G1 to G3. Rsv3 gives resistance to higher numbered more virulent strains G5 to G7. Soybean lines containing Rsv4, are resistant to all seven currently recognized North American SMV strains. In this study, the recently released soybean whole genome sequence was used to design molecular markers for fine mapping Rsv3 to a ~150 kb genomic region containing four coiled-coil nucleotide-binding leucine-rich repeat proteins. In a related study a large population segregating at the Rsv3 locus was screened for resistance to facilitate future characterization of this region. The markers identified in this study will allow for more accurate marker-assisted selection of Rsv3.