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Poster

Session: Session 2 Presenting Authors at Posters (Evens)

P-034 - Evolution of the Rmo2 blast resistance gene accompanied by differentiation of rust and powdery mildew resistance genes in barley and wheat

Thursday, July 17, 2025
13:30 - 15:15  
Location: Confex Hall 3
Crop resistance genetics and genomics

    Presenting Author(s)

  • SA

    Soichiro Asuke

    Graduate School of Agricultural Science, Kobe University
    Kobe, JAPAN

    • Author(s)

  • HH

    Hiroshi Hisano

    Institute of Plant Science and Resources, Okayama University
    Kurashiki, Okayama, Japan

  • MI

    M Thoihidul Islam

    Graduate School of Agricultural Science, Kobe University
    Kobe, Hyogo, Japan

  • EK

    Emi Katayama

    Graduate School of Agricultural Science, Kobe University
    Kobe, JAPAN

  • MS

    Mai Shibata

    Graduate School of Agricultural Science, Kobe University
    Kobe, Hyogo, Japan

  • KS

    Kazuhiro Sato

    Institute of Plant Science and Resources, Okayama University
    Kurashiki, Okayama, Japan

  • YT

    Yukio Tosa

    Graduate School of Agricultural Science, Kobe University
    Kobe, Hyogo, Japan

Blast disease of various gramineous plants is caused by Pyricularia oryzae (syn. Magnaporthe oryzae). This fungus consists of pathotypes that show host specificity at the plant genus level, but there is no Hordeum-specific pathotype. Barley cultivars show various reactions to P. oryzae isolates. Resistant reactions in those interactions are all regulated by a single locus on barley chromosome 7H, designated as Rmo2. Rmo2d is an allele at the Rmo2 locus that recognizes PBY2, an avirulence gene carried by Eleusine and Triticum pathotypes of P. oryzae. We isolated Rmo2 through fine-mapping and complementation assays. Rmo2 encodes tandem kinase protein with heavy metal associated (HMA) domain at its N-terminus. In addition to the barley Rmo2, we also isolated Rwt7, a common wheat (Triticum aestivum) resistance gene which recognizes the avirulence gene PWT7 of the Avena, Lolium, and Eleusine pathotypes. Interestingly, Rwt7 was an ortholog of Rmo2, located on a syntenic region of homoeologous chromosome 7D. Cell death assay using barley protoplasts revealed that HMA domains of Rmo2 and Rwt7 is essential for the recognition of PBY2 and PWT7, respectively. Evolutionary analysis showed that Rmo2 family gene has diverged into orthologs and paralogs recognizing various pathogens including stem rust and powdery mildew fungi through the differentiation of HMA