Development of KASP and SSR Markers for PmQ , a Recessive Gene Conferring Powdery Mildew Resistance in Wheat Landrace Qingxinmai

A recessive gene PmQ conferring powdery mildew resistance was previously localized on the long arm of chromosome 2B in winter wheat landrace Qingxinmai. Breeder-friendly molecular markers are necessary for introgressing this gene into adapted wheat backgrounds for developing disease-resistant wheat cultivars. Three Kompetitive allele-specific PCR (KASP) markers were developed and validated based on SNP variants detected by Bulked segregant analysis-RNA-Seq (BSR-Seq) analysis using a recombinant inbred population derived from cross Qingxinmai × 041133. Two polymorphic SSR markers were also developed from the motifs in the Chinese Spring reference genome sequences of the target genomic region. Those markers were incorporated into a more saturated genetic linkage map for PmQ . The two flanking markers, Xicsq405 and Xicsk18 , are 1.1 and 0.9 cM from PmQ , respectively. The KASP marker Xicsk19 produced unique amplification pattern in 158 out of 160 wheat cultivars or breeding lines. This marker with the gene-linked SSR markers Xicsqc , Xicsqd and Xicsq405 provides an efficient means in molecular marker-assisted selection for PmQ in wheat breeding. The corresponding genomic region of PmQ in the Chinese Spring reference genome has a conserved synteny with the genomes of sequenced wheat cultivars and Triticum durum , T. diccocoides , T. uratu , and barley. The annotation of the two genes, TraesCS2B01G517400.1 and TraesCS2B01G517700.1 , associated with plant defense against pathogens placed a start for cloning PmQ .