Research On The Diversity Of Prokayotic Microorganism In The Saline Lakes Of Xinjiang Based On 16S RDNA Sequences

Saline lakes of XinJiang,the largest province in China, accounts for the 13.78% of all the saline lakes above 1km~2 in aera in China. As its arid, saline and alkaline environment, there are many valuable microorganisms in this district, up to days it is still the focus of research on microorganism in extreme environment.Total DNA of samples from eight saline lakes in Xinjiang district were extracted by molecular biology methods. 16S rRNA genes of bacteria from eight saline lakes and those of haloarchaea from two saline lakes were amplified by PCR to construct 16S rRNA gene libraries from which 403 bacterial clones and 202 haloarchaea clones were randomly sel- ected and sequenced for further analysis. Sequences of 16S rRNA genes were submitted to the international molecular data bank (GenBank) for similarity analysis and were cons- tructed as phylogenetic trees for the analysis of phylogeny by PHYLIP(v 3.65)and Mega3. The diversity index of prokayotic microorganisms in the eight saline lakes were calculated respectively by DOTUR and compared with each other. The results show that:(1)Microorganisms similar to the bacterial clones can be classified into eight phylotypes: Proteobacteria, Gram-positive bacteria, Planctomycetes, Chloroflexi, Chlorobi, Acidobacteria, Verrucomicrobia and Unclassified. Proteobacteria and Gram-positive bacteria were dominant in the eight saline lakes for the account of 36.40% and 54.00% respectively. Proteobacteria includes Alpha-,Beta-,Gamma-,and Delta-proteobacteria; Gram-positive bacteria consists of Bacteroidetes, Firmicutes and Actinbacteria.(2)Microorganisms similar to the haloarchaea clones all belong to the family of Halobacteriaceae: Halorhabdus(7.10%), Halobacterium(12.00%), Haloarcula (11.40%),Halorubrum(15.80%), Haloterrigena(35.90%), Natrinema(1.60%), Halopiger(1.10%) and Unclassified(15.20%),(3)More than half of 16S rDNA sequences from bacterial clones have the identity below 97% with known sequences, indicating that there are many potentially new species in Xinjiang saline lakes to be discovered. However, 16S rDNA sequences from the haloachaea clones show that more than 90% of sequenced clones have the identity above 97% with known sequences, meaning that there are rare potentially new haloarchaea in the saline lakes in this study.(4)Comparative analysis of the diversity of prokayotic microorganism between MaNasi Lake and AHongKuLuMu Lake shows that there is distinct difference in the diversity of bacteria where the former is the least diversity and the latter is the most one, while there is nearly the same in the diversity of haloarchaea. It is suggested that bacteria in saline lakes of this study are worth of further research instead of haloarchaea.Results from culture-independent method based on 16S rDNA sequences with statisticccal analysis show that there are abundant prokayotic microorganisms in the saline lakes of Xinjiang, especially in bacteria domain, which are worth of further study and supply with an objective view into the structure and diversity of microorganisms in the saline lakes of Xinjiang.