Uncultured archaeal diversity in cold spring sediment of Shawan, Xinjiang, China

Abstract:

Abstract: [Objective] We surveyed the composition and diversity of archaea in Xinjiang Shawan cold spring sediment. [Methods] We studied the archaeal diversity in the cold spring sediment by direct extracting environmental DNA with liquid nitrogen grinding method and constructing clone libraries of 16S rRNA gene amplified with archaeal-speci?c primers. Amplified 16S rRNA gene fragments were analyzed by Restriction Fragment Length Polymorphism (RFLP), and the unique RFLP patterns were selected for sequencing, alignment and constructing 16S rRNA gene phylogenetic tree. [Results] A total of 121 positive clones were randomly screened from the library and 22 Operational Taxonomic Units (OTUs) were determined. BLAST analysis indicated that all OTUs were affiliated with the phylum Crenarchaeota. Phylogenetic analysis classified them into two subgroups of Soil-Freshwater-subsurface group, and Marine group I and represented 50% of total clones, respectively. Of them, clones with the potential to assimilate nitrate accounted for 40% of the total archaeal clones. In addition, 40% of clones were related to the cold-loving Crenarchaeota. [Conclusion] These results suggested that the spring sediment harbors a low diversity of archaea, however, a large fraction of Crenarchaeota indigenous species might exist and well adapted to the cold and oligotraphic environment.

Key words:Keywords: cold spring; groundwater; achaea; 16S rRNA homogeny