Fine mapping of the R-SC8 locus and expression analysis of candidate SMV resistance genes in soybean

摘要

Soybean mosaic disease, caused by soybean mosaic virus (SMV), is one of the most broadly distributed viral diseases of soybean (Glycine max [L.] Merr.) worldwide, which decreases seed quality and causes serious losses in yields. The accession Kefeng No.1' was previously shown to carry the R-SC8 gene on chromosome 2, which confers resistance to SMV strain SC8. To fine map the R-SC8 gene, we generated larger F-2 population (2122 plants) from the cross between resistant accession Kefeng No.1' and susceptible variety Nannong 1138-2'. Using eight genomic-SSR markers including four newly developed markers, we mapped this gene to a 30.8-kb region containing two annotated genes between two markers, ZL-42 and ZL-52, on chromosome 2. The expression of genes Glyma.02G121500 and Glyma.02G121600 (encoding MADS-box proteins) was higher in Kefeng No.1' plants than that in Nannong 1138-2' plants, as determined by quantitative reverse transcription-polymerase chain reaction (QRT-PCR). These results suggest that the two genes are likely involved in conferring SMV resistance. This study willfacilitate marker-assisted selection of this gene for use in soybean breeding programmes.