八门湾红树林土壤芽胞杆菌分离与多样性分析

Isolation and diversity analysis of Bacillus-like species from Bamen Bay mangrove soil

摘要:

【目的】了解八门湾红树林海漆林区土壤中可培养芽胞杆菌资源的多样性。【方法】采用水浴处理与直接涂布相结合的方法选择性分离土壤中的芽胞杆菌; 利用16S rDNA PCR-RFLP与16S rDNA序列分析技术研究可培养芽胞杆菌资源的遗传多样性和系统发育关系。【结果】16S rDNA PCR-RFLP酶切图谱UPGMA聚类分析表明, 在100%的相似性水平上, 分离的155株芽胞杆菌分属21个遗传类群, 显示了较为丰富的遗传多样性; 由21种遗传类型代表菌株的16S rDNA 序列分析结果得知, 这些芽胞杆菌主要分布在Bacillaceae和Paenibacillaceae科下的Bacillus、Halobacillus、Virgibacillus和Paenibacillus 4个属, 其中Bacillus为优势属; 有8株芽胞杆菌的16S rDNA序列与数据库中相应模式菌株的最大相似性在95.1%?99.0%之间。【结论】八门湾红树林土壤可培养芽胞杆菌有着较为丰富的遗传多样性, 并存在新的芽胞杆菌物种资源。

Abstract:

[Objective] Analyze microbial diversity of Bacillus-like group isolated from soil samples in Excoecaria agallocha forest, Bamen Bay mangrove. [Methods] The low dilution soil suspensions with heat shock treatment and the high dilution soil suspensions without heat treatment were spread onto Petri dishes for isolating Bacillus-like group species selectively. Their genetic diversity and phylogeny were characterized by 16S rDNA PCR-RFLP and 16S rDNA sequence analysis. [Results] In the level of 100% similarity, UPGMA of 16S rDNA PCR-RFLP map showed that 155 isolates were grouped into 21 clusters, which presented abundant genetic diversity. Moreover, 16S rDNA sequence analysis of representative strains of 21 clusters proved that they were distributed in four genera, Bacillus, Halobacillus, Virgibacillus and Paenibacillus, in which Bacillus was the dominant one. Based on the comparison of 16S rRNA gene sequences, the high levels of 16S rRNA gene similarities of eight strains with the corresponding type strains ranged from 95.1% to 99.0%. [Conclusion] Cultivable Bacillus-like group species isolated from Bamen Bay mangrove soil revealed high genetic diversity and there existed some new species.