A wheat stripe rust adult plant resistant gene YrJ262 mapping within a spontaneous terminal deletion in the short arm of chromosome 3B

Wheat stripe (or yellow) rust, caused by Puccinia striiformis f. sp. tritici , imposes one of the gravest constraints to wheat production. While race-specific seedling resistance genes can be effective in controlling this disease, those which confer resistance at the adult stage typically protect the host from infection by a broad spectrum of the pathogen, and tend to be more durable. But the durable resistance such as that expressed by the recently developed Chinese cultivar (cv.) Jimai 262 is poorly understood. Based on the identification of a spontaneous loss-of-function mutant, a genetic analysis indicated that cv. Jimai 262’s adult plant resistance to stripe rust is conferred by the presence of a single dominant gene, tentatively designated YrJ262 . Bulk segregant exome sequencing implied that the distal end of chromosome arm 3BS of the mutant lacked a ~ 73 Mbp segment which was present in cv. Jimai 262, thereby placing YrJ262 within this segment. The presence of this deletion was confirmed by a fluorescence in situ hybridization-based analysis. The flanking sequences of the Yr30 candidate region were identical between plants carrying Yr30 and cv. Jimai 262, consistent with the hypothesis that Yr30 and YrJ262 co-locate within the same locus. The YrJ262 was complemented by resistant alleles at the QTL on chromosomes 1B and 4B for sufficient adult plant resistance in Jimai 262.