A Unique Expression Profile Responding to Powdery Mildew in Wild Emmer Wheat D430

Powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is a disease that seriously harms wheat production and occurs in all wheat-producing areas around the world. Exploring Pm gene(s) and developing resistant cultivars are preferred to control the disease. Wild emmer wheat (Triticum dicoccoides, 2n = 4x = 28, AABB) has accumulated abundant gene resources for resistance to powdery mildew during the long process of natural evolution. In the current study, the WEW accession D430 was highly resistant to powdery mildew at the whole-growth stage. Genetic analysis showed that the powdery mildew resistance in D430 was conferred by a single dominant locus or gene by the cross of D430 and susceptible durum wheat 647, tentatively named PmD430. Combining BSR-Seq analysis, molecular mapping, and sequence alignment, PmD430 was finally mapped to Pm4 locus, and the sequence was identical to Pm4b. Subsequently, 1871 DEGs between resistant and susceptible bulks were annotated and analyzed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment. Eight disease-related genes were evaluated by qRT-PCR and exhibited a unique expression pattern when invaded by Bgt isolate E09 and was, therefore, presented as latent targets for regulating powdery mildew resistance in D430.