Microsatellite mapping of the powdery mildew resistance gene Pm5e in common wheat (Triticum aestivum L.).

Powdery mildew, caused by Erysiphe graminis DM f. sp. tritici (Em. Marchal), is one of the most important diseases of common wheat world-wide. Chinese wheat variety 'Fuzhuang 30' carries the powdery mildew resistance gene Pm5e and has proven to be a valuable resistance source of powdery mildew for wheat breeding. Microsatellite markers were employed to identify the gene Pm5e in a F(2) progeny from the cross 'Nongda 15' (susceptible) x 'Fuzhuang 30' (resistant). The gene Pm5e was mapped in the distal region of chromosome 7BL. Seven microsatellite markers were found to be linked to the gene Pm5e, of which two codominant markers Xgwm783 and Xgwm1267 were relatively close to Pm5e with a linkage distance of 11.0 cM and 6.6 cM, respectively. It is possible to use the 136-bp allele of Xgwm1267 in 'Fuzhuang 30' for marker-assisted selection during the wheat resistance breeding process for facilitation of gene pyramiding. The mapping information in the present study provides a starting point for fine mapping of the Pm5 locus and map-based cloning to clarify the molecular structure and function of the different alleles at the Pm5 locus. A microsatellite linkage map of chromosome 7B was constructed with 20 microsatellite loci, nine on the short arm and 11 on the long arm. This information will be very useful for further mapping of agronomically important genes of interest on chromosome 7B.