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RMo1 Confers Blast Resistance in Barley and Is Located within the Complex of Resistance Genes Containing Mla, a Powdery Mildew Resistance Gene

September 2006 , Volume 19 , Number  9
Pages  1,034 - 1,041

Tsuyoshi Inukai , 1 M. Isabel Vales , 2 Kiyosumi Hori , 3 Kazuhiro Sato , 3 and Patrick M. Hayes 2

1Graduate School of Agriculture, Hokkaido University, Sapporo, Japan; 2Department of Crop and Soil Science, Oregon State University, Corvallis, Oregon, U.S.A.; 3Research Institute for Bioresources, Okayama University, Kurashiki, Japan

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Accepted 17 April 2006.

Isolates of Magnaporthe oryzae (the causal agent of rice blast disease) can infect a range of grass species, including barley. We report that barley Hordeum vulgare cv. Baronesse and an experimental line, BCD47, show a range of resistance reactions to infection with two rice blast isolates. The complete resistance of Baronesse to the isolate Ken 54--20 is controlled by a single dominant gene, designated RMo1. RMo1 mapped to the same linkage map position on chromosome 1H as the powdery mildew resistance locus Mla and an expressed sequence tag (k04320) that corresponds to the barley gene 711N16.16. A resistance quantitative trait locus (QTL), at which Baronesse contributed the resistance allele, to the isolate Ken 53--33 also mapped at the same position as RMo1. Synteny analysis revealed that a corresponding region on rice chromosome 5 includes the bacterial blight resistance gene xa5. These results indicate that a defined region on the short arm of barley chromosome 1H, including RMo1 and Mla, harbors genes conferring qualitative and quantitative resistance to multiple pathogens. The partial resistance of BCD47 to Ken53--33 is determined by alleles at three QTL, two of which coincide with the linkage map positions of the mildew resistance genes mlo and Mlf.

Additional keywords: Blumeria graminis f. sp. hordei , Oryza sativa .

© 2006 The American Phytopathological Society