Molecular Characterization of All-Stage and Adult-Plant Resistance Loci Against Powdery Mildew in Winter Wheat Cultivar Liangxing 99 Using BSR-Seq Technology

Abstract

Winter wheat cultivar Liangxing 99, which carries gene <i>Pm52</i>, is resistant to powdery mildew at both seedling and adult-plant stages. An F_2:6 recombinant inbred line population from cross Liangxing 99 × Zhongzuo 9504 was phenotyped with <i>Blumeria graminis</i> f. sp. <i>tritici</i> isolate <i>Bgt27</i> at the adult-plant stage in four field tests and the seedling stage in a greenhouse test. The analysis of bulk segregant RNA sequencing (BSR-Seq) identified a single-nucleotide polymorphism-enriched locus, <i>Qaprpm.caas.2B</i>, on chromosome 2BL in the same genomic interval of <i>Pm52</i> associated with the all-stage resistance (ASR) and <i>Qaprpm.caas.7A</i> on chromosome 7AL associated with the adult-plant resistance (APR) against the disease. <i>Qaprpm.caas.2B</i> was detected in a 1.3 cM genetic interval between markers <i>Xicscl726</i> and <i>XicsK128</i> in which <i>Pm52</i> was placed with a range of logarithm of odds (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 <i>Qaprpm.caas.7A</i> was localized in a 4.6 cM interval between markers <i>XicsK7A8</i> and <i>XicsK7A26</i> and explained the phenotypic variation of MDS ranging from 13 to 16%. The results of this study confirmed <i>Pm52</i> for ASR and identified <i>Qaprpm.caas.7A</i> for APR to powdery mildew in Liangxing 99.