Aegilops mutica (genome T) harbors stripe rust resistance and is a potentially valuable genetic resource for broadening the genetic basis of disease resistance in common wheat. A dominant Ph1 -suppression system in Ae. mutica promotes homoeologous pairing and recombination between wheat and alien chromosomes even in the presence of Ph1 , providing a tool for alien gene mapping and introgression. In this study, we identified an all-stage stripe rust resistance gene, Yr1T , in Ae. mutica and mapped it to chromosome 1 T using chromosome deletion lines of Langdon × Ae. mutica amphidiploids. Genetic stocks with an AABBTD genomic constitution were generated by crossing resistant amphidiploids with the susceptible common wheat cultivar MX169. We induced homoeologous recombination between chromosome 1 T and wheat homoeologous group 1 chromosomes by leveraging the Ae. mutica Ph1 -suppression system. Integrating cytological identification, molecular markers, and RNA-seq breakpoint mapping, Yr1T was delimited to an approximately 20 Mb physical interval near the centromere in chromosome arm 1TS. Screening of a 100-plant F 2 population yielded six recombinant plants with different breakpoints (6% recombination frequency), and a translocation line carrying Yr1T was developed. Collectively, these results demonstrated the high efficiency of the Ae. mutica Ph1- suppression system for alien gene mapping and targeted transfer, providing a practical reference for its application in wheat breeding.
Xiang et al. (Sun,) studied this question.