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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。
Using dilution plate method, 267 strains of endophytic bacteria were isolated from the roots, stems and leaves of healthy tobacco. Diversity of these isolates was analyzed using bacterial colony characterization and 16S rRNA sequences. Eight morphological traits of the colony were compared by numerical analysis. Cluster analysis was performed by means of cluster-average linkage clustering method, which could be divided into five clusters and 56 subgroups at the level of 2.15. Phylogenetic analysis of 16S rDNA sequences showed that 267 isolates could be divided into 21 groups. Studies have shown that the same colony morphology strains in the phylogenetic tree are not necessarily clustered together, colony morphology and molecular biology methods classification results are not exactly the same. Clone sequencing analysis showed that these 267 isolates had 98% 99% identity with 21 known species of 6 kinds of bacteria in GenBank respectively. Among them, Bacillus is the dominant species of tobacco-culturable endophytic bacteria.