Fine Mapping a Broad-Spectrum Powdery Mildew Resistance Gene in Chinese Landrace Datoumai, PmDTM , and Its Relationship with Pm24

Powdery mildew, caused by the biotrophic fungal pathogen f. sp. ( ), is a globally important wheat disease causing severe yield losses, and deployment of resistant varieties is the preferred choice for managing this disease. Chinese wheat landrace Datoumai was resistant to 22 of 23 isolates at the seedling stage. Genetic analysis based on the inoculation of isolate E09 on the F , F , and F populations derived from the cross Datoumai × Huixianhong revealed that the powdery mildew resistance of Datoumai is controlled by a single dominant gene, temporarily designated as . Bulked segregant analysis and simple sequence repeat mapping with 200 F plants showed that was located in the same genetic region as on chromosome 1DS. To fine map , 12 critical recombinants were identified from 1,192 F plants and delimited to a 0.5-cM to interval covering 180.5 Kb (38,728,125 to 38,908,656 bp) on chromosome 1DS, and only one highly confident gene, , was annotated within this region. encodes a receptor-like serine/threonine-protein kinase (STK), and a 6-bp deletion in exon 5 may confer the resistance to powdery mildew. Allele frequency analysis indicated that the allele with 6-bp deletion was only present in three landraces (Datoumai, Chiyacao [ ], and Hulutou) and was absent in all of the 353 Chinese modern cultivars and 147 foreign cultivars. These results demonstrate that is mapped to the same locus as and can be widely used to enhance powdery mildew resistance in wheat growing regions worldwide.