油樟内生芽孢细菌的系统发育多样性

Phylogenetic diversity of endophytic endospore-forming bacteria isolated from Cinnamomum longepaniculatum N. Chao ex H. W. Li

【目的】为了解油樟产芽孢内生细菌的多样性。【方法】采用改良的牛肉膏琼脂培养基分离、去除冗余及芽孢染色,测定所得产芽孢内生细菌的16S rRNA基因,进行系统发育分析。【结果】40株产芽孢内生细菌数量占分离得到的内生细菌总数的38.1%,其中根、茎、叶中分别分离得到24株、7株和9株。16S rRNA基因序列系统发育分析结果表明,35株菌可能分属于Bacillus、Lysinibacillus、Paenibacillus属的16个种,还有5株菌的序列与数据库中典型菌株序列相似性低于97%,代表着潜在新类群的存在。【结论】从油樟3个部位分离出的产芽孢内生细菌存在明显的系统发育多样性,而且3个部位分离出的产芽孢内生细菌区系既呈现出一定程度的细菌区系相似性,又表现出器官细菌区系的特异性。

[ Objective ] In order to study the diversity of endophytic endospore-forming bacteria in Cinnamomum longepaniculatum. [ Methods] We took modified nutrient agar medium for isolation and cultivation and analyzed the 16S rRNA gene sequences of the isolates. [ Results ] Forty non-redundant endospore-forming bacterial isolates were ascertained, which accounted for 38.1% of all the endophytic bacterial isolates. Of them, 24 isolates were from roots, 7 from stems and 9 from leaves. Phylogenetic analysis based on 16S rRNA gene sequences showed that 35 of them belonged to 16 species of the genera Bacillus, LysinibaciUus and Paenibacillus, and 5 isolates with 〈 97 % sequence similarities to their closely related members were presumed to be potential novel species. [ Conclusion] The results showed that the cultivable endospore-forming bacteria diversity was abundant and there were some potential novel strains in Cinnamomum longepaniculatum. The microflora of endophytic endospore-forming bacteria in individuals of C. longepaniculatum showed that some bacteria distributed in different organs, but the others were organ-specific bacteria.