江苏省小麦苗枯病菌的遗传多样性初析

Genetic diversity of wheat pathogen Clavibacter fangii from Jiangsu Province,China

采用ER IC-PCR、BOX-PCR和ITS技术,对江苏省6个市的24个小麦苗枯病菌(C lavibacter fangii)进行遗传多样性分析,并与其他10种病原细菌进行比较。结果表明,在相似率达60%时,ITS将24个小麦苗枯病菌分成了5簇。以相似性60%为界,ER IC-PCR将34个参试菌株分为14簇,而BOX-PCR只得到9簇,暗示这两种短重复序列在基因组中的分布不同;将两者电泳图谱结合,得到介于上述两者间的结果,所有菌株被分成12簇,24个小麦苗枯病菌分布在5簇中。3种分析方法相互验证,均说明江苏省小麦苗枯病菌基因组存在显著多样性。ER IC-PCR和BOX-PCR聚类证明了小麦苗枯病菌与棒形杆菌属(C lavibacter)亲缘关系较近,与其他属细菌亲缘关系较远。ER IC-PCR和BOX-PCR扩增基因组DNA指纹比ITS图谱具有更强的多样性。

Twenty-four Clavibacterfangii strains collected from six cities of Jiangsu Province and ten other phytopathogenic bacteria were analysed according to genotypic typing methods including BOX-PCR, ERIC-PCR, and ITS profiling （PCR ribotyping）. The analysis of ITS gene gave 5 clusters of Cl. fangii at the level of 60% similarity after dendrogram analysis. ERIC-PCR revealed that there were 14 clusters in 34 strains, while with BOX-PCR method only nine （ maximum similarity approx 60% ）. At the level of 60% similarity, the combination of ERIC- PCR and BOX-PCR profiles gave 12 clusters of 34 strains, 24 Cl. fangii strains among which were divided into 5 clusters. In summary, the results of ERIC-PCR and BOX-PCR dendrogram analysis suggest that Cl. fangii is only genetically close related to genus Clavibacter, and that ERIC-PCR and BOX-PCR are higher discriminatory techniques than ITS profiling for detecting genetic variation among strains and for identification as well as classification studies.