Fine Mapping of Wheat Adult-plant Resistance Gene Lr12 to Leaf Rust
The adult plant resistance gene Lr12 exhibits excellent resistance in production systems.To fine map and develop reliable molecular markers for Lr12,a cross was made between the susceptible variety Thatcher and the resistant near-isogenic line RL6011 containing the Lr12 gene.The F,generation resulting from this cross was self-pollinated to generate F2 individual plants and F2∶3 families.Field evaluations were conducted using a mixture of five highly virulent leaf rust pathotypes(PHTT,THKS,THTT,PHTS,and PHKS)to inoculate F2 individual plants and F2∶3 families for adult plant resistance assessment and genetic analysis of resistance.Subsequently,genotyping was performed using a 16K liquid chip on 10 resistant and 10 susceptible individuals from the F2 generation to iden-tify SNP markers closely linked to Lr12.This enabled the determination of the chromosomal physical interval contai-ning the resistance gene,the development of SSR molecular markers,and the construction of a genetic linkage map.The results indicate that the segregation ratio of resistance to leaf rust in 3 494 F2 individuals derived from the RL6011(Lr12)/Thatcher cross was consistent with a 3:1 ratio(x3∶1 2=0.14;P=0.71).In the assessment of 685 F2∶3 families,the segregation ratio among resistant individuals,resistant heterozygous individuals,and susceptible individuals conformed to a 1∶2∶1 ratio(x1∶2∶1 2=2.01;P=0.37),suggesting that Lr12 is a dominant gene and the population segregation follows Mendelian single-gene inheritance patterns.Genetic linkage map analysis localized the adult plant leaf rust resistance gene Lr12 between SSR molecular markers YK12817 and YK12928,within a ge-netic interval of 0.38 cM.This corresponds to a physical interval of 2.09 Mb within the physical range of 579.44 Mb to 581.53 Mb on chromosome 4BL of the Chinese Spring reference genome(IWGSC.Ref.V1.0).These findings provide a solid basis for predicting candidate genes.
万方数据
维普
