Development of resistance gene analog markers linked to the stripe rust resistance gene YrH52 derived from wild emmer wheat, Triticum dicoccoides.

摘要

The wheat stripe rust resistance gene YrH52 derived from wild emmer wheat, Triticum dicoccoides, was previously identified and mapped on the short arm of chromosome IB using microsatellite, AFLP and RAPD markers. In this study, we have used disease resistance gene analog (RGA) markers to tag YrH52 and identify closely linked markers. Forty-three degenerated oligonucleotide primers, with a total of 402 primer combinations, were employed to detect RGA markers flanking the YrH52 gene region. An improvedtechnique for exploring RGAs was used based on automated laser fluorescence (ALF) sequencer. Using the bulked segregant analysis of resistance and susceptible DNA pools, we were able to identify 18 RGA markers linked to YrH52. In addition, three new Gatersleben wheat microsatellite markers were also mapped in this region. Of the 18 RGA markers, eight were clustered together and were mapped as tightly linked to YrH52. These results demonstrate the usefulness of RGA sequences, when used in combination with bulked segregant analysis, to rapidly generate markers tightly linked to resistance loci in crop species. The molecular markers obtained in this study should be useful in cloning of YrH52 and marker-assisted selection for pyramiding of YrH52 with other stripe rust resistance genes by marker-assisted selection.