烟草可培养内生细菌的分离及多样性分析

采用稀释平板法, 从健康烟草的根、茎、叶组织中分离到267株内生细菌。利用细菌菌落表征性状和16S rRNA序列对这些分离物进行了多样性分析。通过数值分析比较了8个菌落形态表征性状, 以类平均连锁聚类法的方式进行聚类分析, 在2.15的水平上可分成5个聚类群和56个亚群。16S rDNA序列系统发育分析表明267株分离物可分为21个类群。研究表明同一菌落形态类型的菌株在系统发育树中不一定聚为一类, 菌落形态分类与分子生物学方法分类结果不完全一致。经克隆测序分析表明, 这267株分离物分别与GenBank中6类细菌中的21个已知种相似性达到98%?99%。其中芽孢杆菌属(Bacillus)细菌是烟草可培养内生细菌的优势种群。

Diversity of cultivable endophytic bacteria isolated from tobacco

267 endophytic bacteria of tobacco were isolated from roots, stems and leaves by the method of grinding separation. A preliminary analysis was made on the diversity of the isolates by phenotypic characteristics and molecular classification methods based on partial 16S rDNA sequences, the analyti-cal comparison was also made between them. 267 bacteria isolates were separated with 8 different phenotypic characteristics, and were grouped into 5 clusters and 56 subclusters at the level of 2.15 with numerical classified based on the unweighted pair group method with arithmetic averages algorithm, and they were clustered into 21 molecular groups based on partial 16S rDNA sequences. The results show that there are much more phenotypic types than molecular groups, phenotypic characteristics was not consis-tent with the results of molecular classification exactly. The result of sequence analysis of the 16S rDNA showed a 98%?99% homology with 21 species in the GenBank. The dominant bacterial groups of to-bacco endophytic bacteria belong to Firmicutes, Bacillus genera.