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番茄晚疫病是河北省番茄生产上最具毁灭性的病害之一,对引起该病害的致病疫霉群体结构进行分析有利于病害的防治。利用对峙培养法和菌落直径法对2007-2008年采自河北省保定、沧州和唐山分离自番茄的49个致病疫霉菌株进行了交配型和甲霜灵抗性的表型测定,结果表明该群体所有菌株均为A1交配型,以甲霜灵敏感菌株为主,抗性菌株仅7株。利用聚合酶链式反应-限制性片段长度多态性(PCR-RFLP)、简单序列重复(SSR)和扩增片段长度多态性(AFLP)等分子技术对该群体的基因型进行了分析,结果表明供试菌株线粒体基因型均为Ia型,共鉴定出了Ⅰ、Ⅱ和Ⅲ3种SSR基因型,AFLP聚类分析在相似系数0.87时可以形成α、β和γ等3个不同的分支。河北省所有番茄上致病疫霉菌株均分布在α分支上,该分支又可进一步分为7个亚分支。AFLP亚分支与甲霜灵抗性和地理来源均无明显相关性,但Ⅱ型SSR与甲霜灵抗性和地理来源有明显的相关性。综合表型和基因型数据说明河北省番茄上致病疫霉群体结构比较单一,遗传多样性程度较低。
The late blight of tomato is one of the most destructive diseases in tomato production in Hebei Province. The analysis of the structure of the pathogenic Phytophthora infestans causing this disease is good for the prevention and cure of the disease. 49 strains of Phytophthora infestans isolated from tomato from Baoding, Cangzhou and Tangshan in Hebei Province in 2007-2008 were tested for phenotype of mating type and metalaxyl by confrontation culture method and colony diameter method All the strains in this group were all A1 mating type, mainly metalaxyl-sensitive strains, and only 7 resistant strains. The genotypes of this population were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), simple sequence repeat (SSR) and amplified fragment length polymorphism (AFLP) The results showed that the mitochondrial genotypes of the tested isolates were type Ia, and three SSR genotypes Ⅰ, Ⅱ and Ⅲ were identified. AFLP clustering analysis showed that there were 3 different branches of α, β and γ at the similarity coefficient of 0.87. Phytophthora infestans isolates from all tomato plants in Hebei Province were all distributed on the alpha branch, which was further subdivided into seven sub-branches. There was no significant correlation between AFLP subfractions and metalaxyl resistance and geographical origin, but there was a clear correlation between SSR and metalaxyl resistance and geographic origin. The comprehensive phenotype and genotype data indicated that the structure of P. infestans population on tomato in Hebei Province is single and the degree of genetic diversity is low.