Submitted to: International Plant Protection Congress
Publication Type: Abstract Only
Publication Acceptance Date: 1/12/2003
Publication Date: 5/1/2004
Citation: Chen, X., Yan, G.P., Soria, M.A., Dubcovsky, J., Hayes, P.M. 2004. Rgap, sts, and caps markers for disease resistance genes in wheat and barley. International Plant Protection Congress.
Technical Abstract: Resistance gene analog polymorphism (RGAP), which utilizes high-resolution electrophoresis and sensitive detection of polymerase chain reaction (PCR) products amplified with primers based on conserved domains of plant resistance genes, was used to identify molecular markers for genes in barley and wheat conferring resistance to diseases especially stripe rusts. Co-segregating or tightly linked RGAP markers, together with other types of markers, were used to map numerous genes or quantitative trait loci (QTL) in barley conferring resistance to stripe rust (Puccinia striiformis f. sp. hordei), leaf rust (P. hordei), scald (Rhynchosporium secalis), net blotch (Pyrenophora teres), scab (Gibberella zeae) and barley yellow dwarf virus (BYDV), and in wheat for resistance to stripe rust (P. striiformis f. sp. tritici). Some of the RGAP markers were used in screening germplasms and breeding lines possessing the particular resistance genes. For Yr5, a wheat gene conferring resistance to all races identified so far in the US, sequence tagged site (STS) and cleaved amplified polymorphic sequence (CAPS) markers were developed from co-dominant RGAP markers that co-segregated with the Yr5 locus and had high sequence homology with numerous plant resistance genes. The further developed RGAP-STS-CAPS markers were more robust, easier to score, and able to be used in crosses of the gene donor with a much wider range of wheat genotypes than the original RGAP markers, but also kept the accuracy. The markers are currently used to incorporate the resistance genes into commercial cultivars and combine different genes for durable resistance.