Mapping and characterization of a novel adult-plant leaf rust resistance gene Lr16G216 via BSA and conventional linkage method

Abstract Leaf rust (Puccinia triticina) is one of the most devastating fungal diseases of wheat (Triticum aestivum L.). Discovery and identification of new resistance genes is essential to develop disease-resistant cultivars. An advanced breeding line Yang16G216 was previously identified to confer adult plant resistance (APR) to leaf rust. In this research, a recombinant inbred line (RIL) population was constructed from the cross between Yang16G216 and a highly susceptible line Yang16M6393, and genotyped with exome capture sequencing and 55K SNP array. Through bulked-segregant analysis (BSA) and genetic linkage mapping, a stable APR gene, designated as Lr16G216, was primarily detected and mapped to the distal region of chromosome arm 6BL with a genetic interval of 2.8-cM. For further verification, another RIL population derived from the cross between Yang16G216 and a susceptible wheat variety Yangmai 29 were analyzed using the enriched markers in the target interval, and Lr16G216 was further narrowed to a 0.59-cM genetic interval flanked by the KASP markers Ax109403980 and Ax95083494, corresponding to the physical position 712.34–713.94 Mb in the Chinese Spring reference genome, in which twenty-six disease resistance-related genes were annotated. Based on leaf rust resistance spectrum, mapping data and physical location, Lr16G216 is identified to be a novel and effective APR gene. The Lr16G216 with linked markers will be useful for marker-assisted selection in wheat resistance breeding.