基于16S rRNA和HSP60基因序列分析粘细菌孢囊杆菌亚目形态分类的种属之间的亲缘关系

Phylogenetic analysis of the 16S rRNA and HSP60 gene sequences of the morphology-based taxa of myxobacteria

摘要:

【目的】利用16S rRNA和HSP60基因分子标记分析鉴定形态分类特征不稳定的粘细菌种属。【方法】利用粘细菌的传统分离纯化方法从土壤中分离粘细菌，根据菌株的形态特征进行分类，PCR方法扩增菌株的16S rRNA和HSP60基因序列并进行系统发育关系分析。【结果】根据形态特征，分离得到的15株粘细菌菌株归入孢囊杆菌亚目（Cystobacterineae）的2个科3个属。其中11株粘细菌具有典型的所在种属的子实体结构，而菌株0085-4、0121-3、NM03和Myx9736的子实体结构发生了不同程度退化。15株粘细菌的16S rRNA基因序列的相似性在95.4%到99.5%之间。而HSP60基因序列差异较大。【结论】在属水平上，粘细菌形态分类特征和16S rRNA基因系统进化关系具有很好的一致性；在揭示粘细菌种间系统发育关系中，HSP60基因序列更为适用。

Abstract:

[Objective] Using the 16S rRNA or HSP60 gene sequences to identify the myxobacteria taxa at the levels of species and genus, which were difficult to be classified by their morphological characteristics. [Methods] 15 myxobacterial strains were isolated using the traditional isolation methods, and classified based on their morphological characteristics. The 16S rRNA and HSP60 gene sequences were amplified by PCR methods, and phylogenetically analyzed. [Results] Eleven strains possessed typical mor-phological characteristics, while the other four strains 0085-4, 0121-3, NM03 and Myx9736 were degenerated of fruiting body structures in different extents. The strains were classified into the suborder Cystobacterineae, located in three genera of two families based on their morphological characteristics. The 16S rRNA gene sequences were 95.4% to 99.5% homology, which were in good consistence with the classification of the morphology-based genera; while the HSP60 gene sequences were in longer phylogenetic distances. [Conclusion] The present morphology-based classification of myxobacteria is highly consistent with the phylogenetic results of 16S rRNA gene sequences at the levels of genera or higher taxa; while HSP60 gene sequences provides a more efficient method for identification of closely related myxobacteria species.