Comparative molecular analysis of the prokaryotic diversity of two salt mine soils in southwest China.

While much is known about the microbial diversity in some hypersaline environments, little is known about those of salt mine tunnel soils. The objective of this study was to conduct a comprehensive phylogenetic comparison of the archaeal and bacterial communities present in Yipinglang salt mine (YPL) and Qiaohou salt mine (QH) tunnels differing in salinity and salt composition using 16S rRNA gene clone libraries. Two hundred twenty-eight sequences for QH and 182 sequences for YPL were analyzed by amplified ribosomal DNA-restriction analysis. Libraries revealed 44 bacterial and 57 archaeal different operational taxonomic units belonging to at least 8 bacterial and 3 archaeal divisions, but not all divisions were observed in both salt mines. The bacterial community affiliated with the Bacteroidetes was the most abundant (60% of clones) in QH, while the community in YPL was dominated by δ-Proteobacteria (45% of clones). All archaeal clones from QH were affiliated with Halobacteriaceae. In contrast, in the YPL library, 49% of clones belonged to Halobacteriaceae, 31% of clones related to unclassified archaea, and 21% of clones belonged to Crenarchaeota. Bioinformatic analysis and comparisons showed that the clone libraries were significantly different between two salt mines.