Fine Mapping of the Wheat Leaf Rust Resistance Gene () and Validation of Its Co-segregation Markers.

Wheat leaf rust, caused by the fungus Eriks. (), is a destructive disease found throughout common wheat production areas worldwide. At its adult stage, wheat cultivar Liaochun10 is resistant to leaf rust and the gene for that resistance has been mapped on chromosome 2BS. It was designated and is the same gene as cataloged gene by pedigree analysis and allelism test. We fine-mapped it using recessive class analysis (RCA) of the homozygous susceptible F plants derived from crosses using Liaochun10 as the resistant, male parent. Taking advantage of the re-sequencing data of Liaochun10 and its counterpart susceptible parent, we converted nucleotide polymorphisms in the interval between the resistant and susceptible parents into molecular markers to saturate the genetic linkage map. Four indel markers were added in the 1.65 cM map of flanked by markers and . Thirty-two recombinants were identified by those two markers from the 984 F homozygous susceptible plants and were further genotyped with additional ten markers. was finally placed in a 314.3 kb region on the Chinese Spring reference sequence (RefSeq v1.0) that contains three high confidence genes: , , and Sequence analysis showed several variations in and between resistant and susceptible parents. One KASP marker and an indel marker were designed based on the differences in those two genes, respectively, and were validated to be diagnostic co-segregating markers for . Our results both improve marker-assisted selection and help with the map-based cloning of .