Integration analysis of quantitative trait loci for resistance to Sclerotinia sclerotiorum in Brassica napus

Much research has identified quantitative trait loci (QTL) for resistance to Sclerotinia sclerotiorum in Brassica. However, the real-world applicability of these QTL for gene discovery and resistance breeding has been hampered by poor inter-study integration. This is due to the use of different mapping populations, environments and diverse markers. In this study, a physical map was constructed based on the recent Brassica napus genome release and used link QTL for resistance to S. sclerotiorum. In total, 353 markers, divided into 146 and 207 on the A and C genomes respectively, were used. This enabled integration of 35 QTLs, including 8 leaf resistance (LR) and 27 stem resistance (SR) QTLs. SR QTLs that were conserved across studies were found on A9 (from 22.5 to 27.5 Mb) and on C6 (from 29.5 to 36.1 Mb). Clusters of nucleotide-binding-site, leucine-rich-repeat-containing candidate resistance genes were identified, which provide key targets for identification of genes for resistance to S. sclerotiorum in B. napus.