| Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici(Pst), is a major disease of wheat that is causing large economic losses in many wheat-growing regions worldwide. Deployment of the Pst resistance genes is one of the most effective approaches to control the disease, but many genes are becoming ineffective due to the evolution of new Pst races. However, the use of Pst effective genes from the non-host species, also called the non-host resistance, may represent an alternative strategy to achieve durable resistance to Pst in wheat. In general, barley(Hordeum vulgare) acts as a non-host to Pst, characterized by an immune reaction in response to the Pst infection. In the current study, we identified three wild barley accessions(H. vulgare ssp. spontaneum) that are susceptible to Pst. Two F2 populations were prepared by crossing the Pst-resistant barley(PI 466050 and PI 466186) and the Pst-susceptible barley(PI 264220 and PI 560559). Genetic analysis revealed that the Pst resistance in barley PI 466050 and PI 466186 is conferred by the same resistance locus on the long arm of chromosome 7H, which was then designated as Rps6. Allelism test proved that Rps6 is allelic to Yrpst Y1 that was identified in the Chinese barley “Y12”, and marker analysis proposed that the Rps6 gene is also present in the US barley “Tamalpais”, suggesting that the Rps6 represents a common resource conferring resistance to Pst.Using a high-density mapping population(ca. 11,000 gametes) we precisely mapped the Rps6 within a 0.14 c M region(500 kb contig in barley) that is colinear to regions in Brachypodium(<94 kb) and rice(<9 kb). Since no candidate gene was identified in these colinear regions, a dedicated positional cloning effort in barley will be required to identify Rps6. The identification of Rps6 conferring resistance to Pst can contribute to our understanding of the mechanisms for durable resistance against this devastating wheat pathogen. |
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