四川省马铃薯晚疫病菌群体表型和遗传变异的分析

An analysis on phenotypic and genotypic variation of Phytophthora infestans in Sichuan Province

致病疫霉Phytophthora infestans引起的晚疫病是马铃薯的一种毁灭性病害。为了对四川省近年马铃薯晚疫病菌进行系统多样性分析,本研究从表现型和基因型两个方面鉴定了四川省马铃薯晚疫病菌的群体多态性。交配型、甲霜灵敏感性和生理小种的鉴定结果发现A1交配型菌株只有2份,A2型有29份,自育型12份;甲霜灵敏感菌株3株,中抗菌株22株,高抗菌株18株;共测定出11个生理小种,其中全毒力小种发生频率最高,占供试菌株的25.58%。基因型鉴定结果表明,43份材料共发现了10种SSR基因型,5个SSR标记在该种群上共产生了16个SSR位点,每个标记平均有3.2个位点,多态性信息含量平均值为0.46,SSR4是多态性最丰富的标记。本试验中A2菌株和自育型的基因型SSR相同,其中全毒力小种是当地的优势致病菌,该研究为今后四川马铃薯晚疫病的有效防控提供理论依据。

The population diversity of Phytophthora infestans, the most destructive pathogen causing potato late blight, in Sichuan Province were identified by phenotypic and genotypic analysis. The mating type, metalaxyl sensitivity and virulence test were included in phenotypic analysis. Amongst 43 isolates tested, two were A1 mating type, 29 were A2 mating type and 12 were self-fertile（SF）. The results of metalaxyl resistivity test indicated that three isolates were resistant, 22 were moderately resistant and eight were sensitive. Eleven virulence types were identified, among which 25.58% of the isolates showed fullvirulence with the highest frequency. Based on genotypic analysis, ten SSR genotypes were found and 16 alleles were yielded in 43 isolates with an average of 3.2 alleles per locus. The mean PIC value was 0.46. SSR4 was the most informative SSR, with the highest PIC value（0.76）. A2 and SF isolates were grouped to the same cluster. Full virulence races were dominant in local potato fields. These results provide a scientific basis for controlling potato late blight in Sichuan Province.