Fine Mapping of Stripe-Rust-Resistance Gene in Common Wheat by BSR-Seq and MutMap-Based Sequencing.

Identification and accurate mapping of new resistance genes are essential for gene pyramiding in wheat breeding. The gene is a dominant stripe-rust-resistance gene located at the distal end of chromosome 2AL, which was identified in a leading Chinese-wheat variety, Jimai 22, showing high resistance to CYR32, a prevalent race of () in China. In the current study, 15 F and 2273 F plants derived from the cross of Jimai 22/Avocet S were used for the fine-mapping of . The RNA-Seq of resistant and susceptible bulks of F plants (designated BSR-Seq) identified 10 single-nucleotide polymorphisms (SNP) in a 12.09 Mb physical interval on chromosome 2AL. A total of 1022 EMS-induced M lines of Jimai 22 were screened, to identify susceptible mutants for MutMap analysis. Four CAPS markers were developed from SNPs identified using BSR-Seq and MutMap. A linkage map for was constructed with 11 CAPS/STS and three SSR markers. was located at a 0.9 cM genetic interval flanked by markers H736 and H400, corresponding to a 340.46 kb physical region (768.7-769.0 Mb), including 13 high-confidence genes based on the Chinese Spring reference genome. is a potential candidate-gene, according to linkage and quantitative real-time PCR (qPCR) analyses. The CAPS marker H732 designed from an SNP in co-segregated with These results provide a useful stripe-rust-resistance gene and molecular markers for marker-assisted selection in wheat breeding and for further cloning of the gene.