ARS | Publication request: A conserved locus conditioning Soil-borne wheat mosaic virus resistance on 5DL in common wheat

Submitted to: Molecular Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 16, 2012
Publication Date: N/A

Interpretive Summary: Soil-borne wheat mosaic virus (SBWMV) is considered one of the most important diseases in winter wheat grown in the central and southeastern United States. Utilization of resistant cultivars is the only practical and environmentally friendly means of control. The genetics of resistance in the soft red winter wheat varieties Pioneer brand 26R61 and AGS 2020 was studied. The resistant parents were crossed to the susceptible wheat lines AGS 2000 and LA 95135 to develop populations that were then grown in virus infected fields and rated for level of resistance. Analysis with DNA markers determined that a gene on the long arm of wheat chromosome 5D was responsible for resistance to the virus in both varieties. This same gene has been found in SBWMV resistant hard winter wheat varieties and in European varieties resistant to Soil-borne cereal mosaic virus. A conserved locus was therefore proposed for conditioning resistance to both viruses in common wheat. Our analysis indicated that the DNA markers identified were suitable for marker-assisted selection for resistance to both diseases in the absence of the pathogen.

Technical Abstract: Soil-borne wheat mosaic virus (SBWMV) is considered one of the most important diseases in winter wheat regions of the central and southeastern United States. Utilization of resistant cultivars is the only practical and environmentally friendly means of control. To identify QTL for SBWMV resistance, two independent RIL (recombinant inbred line) populations, Pioneer 26R61/AGS 2000 (PR61/A2000, 178 lines) and AGS 2020/LA 95135 (A2020/LA, 130 lines), were developed. Pioneer 26R61 and AGS 2020 were resistant to SBWMV, and AGS 2000 and LA 95135 were susceptible. Based on the whole genome genotyping for the PR61/A2000 population and targeted mapping of chromosome 5D for the A2020/LA, the same major QTL QSbm.uga-5DL was identified in all environments with highly significant LOD values, explaining up to 62% and 65% of the total phenotypic variation in the PR61/A2000 and A2020/LA populations, respectively. The location of the resistance QTL coincided with previously published SBCMV resistance genes Sbm1, SbmClaire and SbmTremie on the long arm of chromosome 5D. A conserved locus was therefore proposed for conditioning SBWMV/SBCMV resistance in common wheat. Validation of the QTL using the closely linked markers Xbarc177 and Xbarc161 in 3 cultivars and 3 elite lines with Pioneer 26R61 in their pedigrees indicated that the markers were suitable for marker-assisted selection.