Mining and Genetic Mapping of a Novel Powdery Mildew Resistance Gene, PmKu-2013, Identified in Aegilops tauschii

Abstract

Wheat powdery mildew is a fungal disorder caused by Blumeria graminis f. sp. tritici (Bgt) and is a severe and significant threat to the yield and quality of its host. The most practical and environmentally friendly approach to controlling this disease is through resistance gene identification to develop resistant varieties. Wild germplasm relatives of wheat are a valuable reservoir of genes contributing to resistance against powdery mildew. In our study, we identified the Aegilops tauschii germplasm “KU-2013”, exhibiting seedling resistance to Bgt isolate E09 following hexaploidization. Genetic analysis and chromosomal localization of the powdery mildew resistance gene in doubled haploid (DH) KU-2013 indicated that the disease resistance gene in DHKU-2013 is governed by a dominant gene situated in 5DS, tentatively named PmKu-2013. Following the analysis of PmKu-2013 relative to the genes at the Pm2 locus, it was inferred that PmKu-2013 represented a distinct novel gene separate from Pm2. Using molecular marker analysis, PmKu-2013 was found to be ultimately mapped between the sdau5DS5-3 and sdau5DS6-1 markers, with genetic distances of 0.6 cM and 1.3 cM, respectively. Using markers tightly linked to PmKu-2013, the genotypes of core wheat varieties from various regions were identified, laying the foundation for the transfer and utilization of PmKu-2013 in molecular-assisted selection (MAS) for breeding.