Abstract: Powdery mildew caused by Blumeria graminis f. sp. tritici is one of the most economically important wheat diseases in many regions through out the world. N0308, a common wheat line contains powdery mildew resistance gene introgressed from wild emmer accession G25. Genetic analysis of the F2 populations and F3 families derived from the cross between N0308 and a susceptible common wheat cultivar Shaanyou 225 indicated a single dominant gene, temporarily designated PmG25, conferred resistance to powdery mildew race ‘Guanzhong 4’. Bulked segregant analysis and molecular markers were used to characterize the powdery mildew resistance gene PmG25. Eleven SSR markers (Xgpw1082, Xgpw3191, Xfcp1, Xfcp393, Xfcp394, Xgpw7425, Xwmc75, Xgwm408, Xwmc810, Xbarc232 and Xbarc142) and two EST-STS markers (BF482522 and BF202652) were linked with PmG25 on the long arm of chromosome 5B. The resistance gene was flanked by Xfc1/Xfcp393 and Xgpw3191, with genetic distances of 1.3 and 3.3 cM, respectively, and located on the chromosome bin 5BL-14- 0.75-0.76 in the test with a set of deletion lines. The powdery mildew resistance genes Pm36 and Ml3D232 have also been mapped to the region. The chromosome location and genetic mapping results suggested that the powdery mildew resistance gene derived from wild emmer G25 may be allelic or closely linked to Pm36.
Abstract: Powdery mildew caused by Blumeria graminis f. sp. tritici is one of the most devastating disease of wheat in China and worldwide. A powdery mildew resistance gene, originated from wild emmer accession G25, transferred into a common wheat line N0308. F2 population was established by crossing N0308, resistance to powdery mildew race Guanzong 4, with susceptible line Shaanyou 225. The segregation of phenotype accorded with an expected ratio 3:1. The results indicated that the powdery mildew resistance gene in N0308 controlled by a single dominant gene, designated temporarily as PmG25. SSR markers and the bulk segregant analysis were used to characterize the powdery mildew resistance gene PmG25. Six SSR markers such as Xgpw7425, Xwmc75, Xgwm408, Xwmc810, Xbarc232 and Xbarc142 located on the distal of resistance gene PmG25 with genetic distance 7.4, 9.4, 11.2, 22.3, 25.4 and 29.3 cM, respectively. All markers were placed on chromosome 5BL using Chinese Spring nulli-tetrasomic and ditelosomic lines, suggesting this gene might be located on long arm of chromosome 5B.
Abstract: Summary
Wheat powdery mildew, caused by Blumeria graminis f. sp. tritici is one of the most devastating diseases of common wheat worldwide. To date, 45 loci (Pm1 to Pm45) with 64 genes/alleles for resistance to powdery mildew have been identified and located on 18 different chromosomes in bread wheat. 29 resistance genes/alleles have been tagged with molecular markers such as restriction fragment length polymorphisms (RFLPs), random amplified polymorphic DNAs (RAPDs), amplified fragment length polymorphisms (AFLPs), sequence tagged sites (STS) and simple sequence repeats (SSRs), by using F2, back-cross populations, near-isogenic lines (NILs), doubled haploids (DH), recombinant inbred lines (RILs) or bulked segregant analysis (BSA). The detail information on chromosomal location, molecular markers linked to powdery mildew, mapping population and molecular mapping of powdery mildew resistance genes have been reviewed.
