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

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.