Identification and genetic mapping of PmAF7DS a powdery mildew resistance gene in bread wheat (Triticum aestivum L.)

Genetic mapping of a novel powdery mildew resistance gene in wild emmer wheat from "Evolution Canyon" in Mt. Carmel Israel

A single dominant powdery mildew resistance gene MlNFS10 was identified in wild emmer wheat and mapped within a 0.3cM genetic interval spanning a 2.1Mb physical interval on chromosome arm 4AL. Wheat powdery mildew caused by Blumeria graminis forma specialis tritici (Bgt) is a globally devastating disease. The use of powdery mildew resistance genes from wild relatives of wheat is an effective method of disease management. Our previous research has shown that disruptive ecological selection has driven the discrete adaptations of the wild emmer wheat population on the south facing slope (SFS) and north facing slope (NFS) at the microsite of "Evolution Canyon" at Mount Carmel, Israel and demonstrated that 16 accessions in the NFS population display high resistance to 11 powdery mildew isolates (collected from different wheat fields in China). Here, we constructed bi-parental population by crossing the accession NFS-10 (resistant to 22 Bgt races collected from China in seedling resistance screen) and the susceptible line SFS2-12. Genetic analysis indicated that NFS-10 carries a single dominant gene, temporarily designated MlNFS10. Ultimately, 13 markers were successfully located within the long arm of chromosome 4A, thereby delineating MlNFS10 to a 0.3 cM interval covering 2.1 Mb (729275816-731365462) in the Chinese Spring reference sequence. We identified disease resistance-associated genes based on the RNA-seq analysis of both parents. The tightly linked InDel marker XWsdau73447 and SSR marker XWsdau72928 were developed and used for marker-assisted selection when MlNFS10 was introgressed into a hexaploid wheat background. Therefore, MlNFS10 can be used for improvement of germplasm in breeding programs for powdery mildew resistant cultivars.