Molecular characterization of adult plant resistance loci against powdery mildew in winter wheat cultivar Liangxing 99 using BSR-Seq technology.

Winter wheat cultivar Liangxing 99, which carries gene Pm52, is resistant to powdery mildew at both seedling and adult plant stages. An F2:6 recombinant inbred line (RIL) population from cross Liangxing 99 × Zhongzuo 9504 was phenotyped with Blumeria graminis f. sp. tritici isolate Bgt27 at the adult plant stage in four field tests and the seedling stage in a greenhouse test. The analysis of bulk segregant RNA sequences identified an SNP-enriched locus, Qaprpm.caas.2B, on chromosome 2BL in the same genomic interval of Pm52 associated with the all-stage resistance (ASR) and Qaprpm.caas.7A on chromosome 7AL associated with the adult-plant resistance (APR) against the disease. Qaprpm.caas.2B was detected in a 1.3 cM genetic interval between markers Xicscl726 and XicsK128 in which Pm52 was placed with a range of LOD values from 28.1 to 34.6, and the phenotype variations explained in terms of maximum disease severity (MDS) ranged from 45% to 52%. The LOD peak of Qaprpm.caas.7A was localized in a 4.6 cM interval between markers XicsK7A8 and XicsK7A26 and explained the phenotypic variation of MDS ranging from 13% to 16%. The results of this study confirmed Pm52 for ASR and identified Qaprpm.caas.7A for APR to powdery mildew in Liangxing 99. Keywords: Triticum aestivum; Blumeria graminis f. sp. tritici; Pm52; QTL; BSR-Seq.