Biodiv Sci ›› 2012, Vol. 20 ›› Issue (4): 495-504.DOI: 10.3724/SP.J.1003.2012.10224

• Original Papers • Previous Articles     Next Articles

Population diversity and phylogeny of halophiles in the Qinghai Lake

Derui Zhu1,2*, Jian Liu1, Rui Han3, Guoping Shen2, Fang Yang2, Qifu Long2, Deli Liu1   

  1. 1Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Science, Central China Normal University, Wuhan 430079

    2Medical College of Qinghai University, Xining 810016

    3Qinghai Academy of Agricultural Forestry Sciences, Xining 810016
  • Received:2011-12-06 Revised:2012-05-03 Online:2012-07-20 Published:2012-09-12
  • Contact: Derui Zhu

Abstract: Qinghai Lake is the largest inland saline lake in China, but the diversity of halophiles within the lake remains unknown. We isolated 35 bacterial strains from different water samples in Qinghai Lake using an Oesterhelt-Stoeckenius medium (OSM). The majority of halophiles in this lake were moderate halophiles (grew at 0.4 to 3.5 M NaCl), accounting for about 62.9% (22 strains) of total bacteria, followed by the slight halophiles (22.9%, 8 strains) which could grow at 0 to 1.0 M NaCl, whereas the halotolerant (grew at 0 to more than 1.0 M NaCl) and nonhalophile (grew at 0 to 1.0 M NaCl) represented 11.4% (4 strains) and 2.9% (1 strain) of total bacteria, respectively. We investigated and analyzed the population diversity and evolutionary relationship based on the 16S rDNA sequences. A total of 35 bacterial strains were sequenced, and homology analysis showed that a majority was affiliated with γ-Proteobacteria and Bacilli, which accounted for 68.6% (24 strains) and 17.1% (6 strains) of total bacteria, respectively, whereas Actinobacteridae (3 strains), α-Proteobacteria (1 strain) and Eurotiomycetidae (1 strain) represented a small portion of total bacteria. Based on phylogenetics, 35 strains belonged to 14 different genera. Ten strains of Halomonas in the Oceanospirillales were the most dominant species, whereas 4 strains of Marinomonas represented a minor species component. Overall, Halomonas was the dominant group of moderate halophile, which can likely be attributed to its ability to adapt to relatively low salinity environments.