农杆菌介导的稻瘟病菌致病突变菌株的筛选

 利用1个致病能力非常弱的稻瘟病菌菌株CY2和农杆菌介导T-DNA方法,已成功地获得了5000多个转化子,并以多个转化子混合接种含25个不同抗病基因的近等基因系,获得了30个致病突变体。但突变体针对不同的无毒基因有很大差别,从含有Pi-ta²的F128-1上获得了14个突变体,从含有Pi-a的IRBL-2上获得了7个突变体,从含有Pik-s的IRBL-4上获得了2个突变体,而从其它抗病基因的品系上未发现任何突变体,故T-DNA似乎有插入热点。不同突变体在携带相同抗病基因的品系上的致病性存在很大差异,表明这些近等基因系可能还携带其它抗稻瘟病基因。CY2不能侵染普遍认为不含抗稻瘟病基因的丽江新团黑谷(LTH),而7个突变体则能成功地使其发病,表明LTH亦含有抗稻瘟病基因。

Screening of Agrobacterium tumefaciens-mediated pathogenic mutants of Magnaporthe grisea

By using Agrobacterium tumefaciens-mediated transformation, more than 5 000 transformants were obtained from Magnaporthe grisea CY2, an isolate with very weakly pathogenic to rice. Among 30 pathogenic mutants were screened by inoculation with mixed spore suspension of 20-30 transformants onto the near-iso-genic lines (NIL) contained 25 rice blast resistance genes. Mutation had quite different frequency at different pathogenicity-related loci for the pathogen. No any mutants were found from lines with the other resistance genes while as many as 14, 7 and 2 mutants were found from the line F128-1 carrying Pi-ta², the line IRBL-2 carrying Pi-a and the line IRBL-4 carrying Pik-s, respectively. It was indicating that T-DNA might have insert hot spot in the pathogen. The mutants showed different pathogenic types on the NILs with the same blast resistance gene and it implied that the NILs might carry other resistance genes. LTH, a line without any blast resistance genes considered commonly, might have resistance genes depending on the fact that 7 mutants were harvested from it and could not infected with the wild type CY2.