Wheat blast caused by the Triticum pathotype of Pyricularia oryzae was first reported in 1985 in Brazil and recently spread to Bangladesh. We tested whether Rmg8 and RmgGR119, recently identified resistance genes, were effective against Bangladeshi isolates of the pathogen. Common wheat accessions carrying Rmg8 alone (IL191) or both Rmg8 and RmgGR119 (GR119) were inoculated with Brazilian isolates (Br48, Br5, and Br116.5) and Bangladeshi isolates (T-108 and T-109). Br48, T-108, and T-109 carried the eI type of AVR-Rmg8 (the avirulence gene corresponding to Rmg8) while Br5 and Br116.5 carried its variants, eII and eII’ types, respectively. Detached primary leaves of IL191 and GR119 were resistant to all isolates at 25°C. At a higher temperature (28°C), their resistance was still effective against the eI carriers but was reduced to a low level against the eII/eII’ carriers. A survey of databases and sequence analyses revealed that all Bangladeshi isolates carried the eI type which induced a higher level of resistance than the eII/eII’ types. The resistance of IL191 (Rmg8/−) to the eI carriers was maintained even at the heading stage and at the higher temperature. In addition, GR119 (Rmg8/RmgGR119) displayed higher levels of resistance than IL191 at this stage. These results suggest that Rmg8 combined with RmgGR119 will be useful in breeding for resistance against wheat blast in Bangladesh.

1985年在巴西首次报道了由稻瘟病菌的小麦致病型引起的小麦瘟病，最近又传播到孟加拉国。我们测试了最近鉴定出的抗性基因Rmg8和RmgGR119是否对孟加拉国的病原体有效。用巴西分离株（Br48，Br5和Br116.5）和孟加拉分离株（T-108和T-109）接种单独携带Rmg8（IL191）或Rmg8和RmgGR119（GR119）的普通小麦种质。Br48，T-108和T-109携带eI型AVR-Rmg8（与Rmg8对应的无毒基因），而Br5和Br116.5携带其变体，分别为eII和eII'类型。分离的IL191和GR119初生叶在25°C时对所有分离株均具有抗性。在较高温度（28°C）下，它们对eI载流子的电阻仍然有效，但对eII / eII'载流子的电阻降低到较低水平。对数据库和序列分析的调查显示，所有孟加拉分离株均携带eI型，其诱导的抗性水平高于eII / eII'型。即使在抽穗阶段和较高温度下，IL191（Rmg8 / -）对eI载体的抗性仍保持。另外，在此阶段，GR119（Rmg8 / RmgGR119）显示出比IL191高的抗性水平。这些结果表明Rmg8联合RmgGR119将在育种对孟加拉小麦抗稻瘟病是有用的。