Kobe University, Nada, Kobe, Japan.
Phytopathology. 2012 Jul;102(7):674-82. doi: 10.1094/PHYTO-09-11-0256.
Barley cultivars show various patterns of resistance against isolates of Magnaporthe oryzae and M. grisea. Genetic mechanisms of the resistance of five representative barley cultivars were examined using a highly susceptible barley cultivar, 'Nigrate', as a common parent of genetic crosses. The resistance of the five cultivars against Setaria, Oryza, Eleusine, and Triticum isolates of M. oryzae was all attributed to a single locus, designated as Rmo2. Nevertheless, the Rmo2 locus in each cultivar was effective against a different range of isolates. Genetic analyses of pathogenicity suggested that each cultivar carries an allele at the Rmo2 locus that recognizes a different range of avirulence genes. One allele, Rmo2.a, corresponded to PWT1, which conditioned the avirulence of Setaria and Oryza isolates on wheat, in a gene-for-gene manner. The other alleles, Rmo2.b, Rmo2.c, and Rmo2.d, corresponded to more than one avirulence gene. On the other hand, the resistance of those cultivars to another species, M. grisea, was conditioned by another locus, designated as Rmo3. These results suggest that Rmo2 is effective against a broad range of blast isolates but is specific to M. oryzae. Molecular mapping revealed that Rmo2 is located on the 7H chromosome.
大麦品种对稻瘟病菌和玉蜀黍赤霉病菌的分离株表现出不同的抗性模式。利用高度敏感的大麦品种“黑粒”作为遗传杂交的共同亲本，研究了五个代表性大麦品种抗性的遗传机制。五种品种对稻瘟病菌的 Setaria、Oryza、Eleusine 和 Triticum 分离株的抗性均归因于一个单一的位点，称为 Rmo2。然而，每个品种的 Rmo2 位点对不同范围的分离株有效。致病性的遗传分析表明，每个品种在 Rmo2 位点携带一个等位基因，该等位基因识别不同范围的无毒基因。一个等位基因 Rmo2.a 与 PWT1 相对应，以基因对基因的方式决定了 Setaria 和 Oryza 分离株在小麦上的无毒。其他等位基因 Rmo2.b、Rmo2.c 和 Rmo2.d 对应于一个以上的无毒基因。另一方面，这些品种对另一种病原菌，即玉蜀黍赤霉病菌的抗性由另一个位点 Rmo3 决定。这些结果表明，Rmo2 对广泛的稻瘟病菌分离株有效，但对稻瘟病菌具有特异性。分子图谱表明，Rmo2 位于 7H 染色体上。
