云南两个县陆稻稻瘟病菌稻巨座壳交配型测定及致病性分析

2014年,自云南省沧源县及耿马县陆稻地方品种上分离99个稻瘟病菌稻巨座壳单孢菌株,采用4个已知交配型的标准菌株对其进行育性和交配型测定。结果表明,两地稻巨座壳菌株具较高的育性,平均可交配率高达90.8%,且可育菌株中,MAT1-1和MAT1-2菌株分别占60.9%和39.1%;分别随机对沧源县南撒村和班考村同一田块MAT1-1型和MAT1-2型可育两性菌株进行交配,均能发育形成成熟的子囊孢子,说明该陆稻地区稻巨座壳菌的可育菌株数量丰富,且于适宜条件极有可能产生有性世代;利用22个以丽江新团黑谷为背景、持有不同抗稻瘟病基因的单基因系对分离的99个稻巨座壳菌株的致病性进行测定,明确了不同菌株的致病性,且发现Pik-h、Piz-t、Pi5及Pi9基因表现出良好的抗性,平均抗病频率达到90.0%以上、是抗病育种的优异抗原;同时,菌株对特定抗性基因致病性的明确,也为选用不同菌株的组合开展有性杂交,构建遗传群体开展稻巨座壳菌无毒基因的克隆鉴定奠定了基础。

Determination of mating type and pathogenicity of Magnaporthe oryzae isolates collected from upland rice of two counties of Yunnan,Southwest China

Fertility and mating types of ninety-nine isolates of Magnaporthe oryzae collected from the traditional upland rice varieties in Cangyuan and Gengma counties of Yunnan were tested with four standard tested isolates in 2014. The results showed that the fertility of M. oryzae isolates from these two areas was very high, with the average mating rate of 90.8%. Among the fertile isolates, MAT1-1 and MAT1-2 accounted for 60.9% and 39.1% respectively. The mature ascospores could be produced when crosses were made between the fertile isolates with opposite mating type randomly collected from the same field of Nansa village or Bankao village in Cangyuan County, indicating that the fertile isolates of M. oryzae were very abundant in these upland rice areas, and it was very likely to form perfect stage under suitable conditions. The pathogenicity of 99 M. oryzae isolates detected by using 22 monogenic lines showed that the monogenic lines carrying Pik-h, Piz-t, Pi5 and Pi9, expressed high level of resistance against blast, with an average resistance frequency of more than 90.0% of all tested isolates. The four genes could be the elite germplasm resources for disease-resistant rice breeding. The isolates with high fertility and definite pathogenicity responding to specified resistance genes could be served as the important resources to construct genetic populations for identification and cloning of avirulence genes of M. oryzae.