对分离自紫茎泽兰的19个链格孢菌菌株的致病性进行了比较研究,并对这19个菌株和其它来源的3个菌株的5.8SrDNA及其两侧的ITS1区和ITS2区进行了序列分析.结果显示,链格孢菌菌株的致病性差异明显;21株链格孢菌菌株在5.8SrDNA及其两侧的转录间区(ITS区)的序列无差异,而与百日草链格孢菌(Alternariazinniae)的序列差异显著,表明21株链格孢菌菌株属种内变异.采用AFLP分子标记技术对21株链格孢菌的DNA扩增片段长度多态性进行了分析,结果表明,链格孢菌自然变异群体内存在很高的遗传多样性.链格孢菌菌株的相似性与菌株的地理来源有一定的相关性,但基于AFLP标记划分的AFLP类群与基于寄主病情指数划分的致病力类群间关系不相一致;起始菌株与变异菌株相似性显著,但二者和致病性的关系不显著.图2表1参18The pathogenicity of 19 strains of Alternaria alternata isolated from Eupatorium adenophorum was studied. 5.8S rDNA, ITS1 and ITS2 sequences of 22 strains from crofton weed and other plants were analyzed. The results showed that there were differences in their pathogenicity to crofton weed. The sequence analysis showed that there was no difference among 21 strains in 5.8S rDNA, ITS1 and ITS2 sequences, respectively, but the significant difference occurred between all the 21 A. alternata strains and A. zinniae. This indicated that the variance of all the 21 different strains of A. alternata was interspecific. Amplified fragment length polymorphisms (AFLP) were first used to analyze the DNA diversity of the 21 A. alternata strains. The result showed that there was a very high genetic diversity among natural and variable populations. There were some correlations between genetic similarity and geographical sources of A. alternata. The groups classified based on AFLP patterns were not associated with pathogenicity. Ancestry strains had high similarity with their original ones on genetics, but not on pathogenicity. Fig 2, Tab 1, Ref 18国家"863"项目(2001AA246012);; 国家自然科学基金(No.30170619);; 国家基础研究专项("973"项目,2002CB111402);; 江苏省自然科学基金(BK2001066);; 江苏省博士后基金8590课题资助~
