The male sterility of bread wheat line XN291S was resulted from the deletion of a large segment at the end of 6BS.

The sterile lines used in the production of two-line hybrid wheat in China are mainly photoperiod-thermo sensitive male sterile (PTSMS), and it is of great significance to study the sterile features and mechanisms of novel sterile lines for wheat hybrid breeding. XN291S, a spontaneous mutant of XN291, was sterile under long-day/high-temperature and fertile under short-day/low-temperature. In this study, its male sterility was mainly controlled by the high temperature, and occurred in the binucleate stage. The sterility gene at high temperature was a major recessive XNms-6B gene located on 6BS by genetic analysis and molecular marker genetic mapping, and the large fragment deletion at the end of 6BS was proved by genomic in situ hybridization (GISH), fluorescence in situ hybridization (FISH) and further genomic resequencing. This fragment corresponded to the 0–88.3 Mb physical interval of the Chinese Spring Reference Genome (IWGSCv1.0), and contained 1077 high-confidence genes. The results of multi-omics association analysis showed that starch and sucrose metabolism, phenylpropane biosynthesis, linoleic acid metabolism, and secondary metabolite biosynthesis were the key pathways, and the deleted genes involved in heat stress response and anther development directly or indirectly resulted in the male sterility of XN291S. This study will contribute to further study of XNms-6B, and lay a foundation for the application of this sterile line in hybrid wheat breeding. [ABSTRACT FROM AUTHOR]