Diversity of Actinobacterial community in saline sediments from Yunnan and Xinjiang, China

The diversity and community structures of actinobacteria in saline sediments collected from Yunnan and Xinjiang Provinces, China, were investigated with cultivation and 16S rRNA gene analysis. A total of 163 actinobacterial isolates were obtained, and they were affiliated with the order Actinomycetales (distributed into five suborders: Streptosporangineae, Micrococcineae, Streptomycineae, Pseudonocardineae, and Glycomycineae). A total of 748 actinobacterial 16S rRNA gene clones were examined, and they could be classified into Actinomycetales, Acidimicrobiales, and unclassified actinobacteria. The Actinomycetales sequences were distributed into nine suborders: Streptosporangineae, Glycomycineae, Micromonosporineae, Pseudonocardineae, Corynebacterineae, Frankineae, Propionibacterineae, Streptomycineae, and Micrococcineae. The unclassified actinobacteria contained three new clusters at the level of subclass or order. Our 16S rRNA gene phylogenetic data indicated that actinobacterial communities were very diverse in the investigated saline sediments (salinity 0.4-11.6%) and some actinobacterial members may be halotolerant or halophilic. The actinobacterial community structures in the saline sediments were different from those in marine and freshwater environments. Our data have implications for a better understanding of the distribution of Actinobacteria in saline environments.