Phylogenetic analysis of 16S rRNA gene reveals high species diversity of Halorubrum in China

Accepted 10 May, 2013 Haloarchaea such as Halorubrum are excellent models for field and laboratory study. Almost half of the new species of Halorubrum were identified from the samples collected from China. The aim of this study is to determine whether some species reported elsewhere are distributed in China. Hypersaline environments-a special niche, are distributed all over the world. The genus Halorubrum frequently dominates the microbial communities in hypersaline environment. We collected tens of salt mine or saline soil samples from China’s Yunnan, Hainan and Jiangsu provinces (China) for Halorubrum isolation. Tens of haloarchaea strains with different morphological properties were isolated. The 16S rRNA genes were amplified by using Halorubrum specific primers and cloned into the vector for sequencing. The raw classifications were based on the phylogenetic analyses, and the results showed that 29 strains were affiliated with genus Halorubrum and isolated 29 strains of haloarchaea affiliated with Halorubrum. The 16S rRNA gene sequences were amplified by Halorubrum specific primers. Additional sequences available in GenBank were downloaded. Phylogenetic analyses of 16S rRNA gene sequences revealed: 1) Nineteen lineages, of which eleven shared a low sequence similarity (less than 99%) with the validly described species and, thus, may represent new taxa; 2) new records of five known species also distributed in China; 3) at least two separated lineages may represent new species. This is the first report of such high species diversity of Halorubrum in China. Key word: Halorubrum, rRNA gene sequences, hypersaline, haloarchaea strains.