The Prokaryotal Biogeography And Ecological Strategy In Mud Volcanoes, Xinjiang

To explore microbial diversity, biogeography and ecological strategy from mud volcanoes in Xinjiang, culture-dependent and T-RFLP approachs were used to analyse the microbial diversity and biogeography from four geographic barrier isolated mud volcanoes in Xinjiang. Colony-formation curve analysis was used to investigate the r-K strategy microbial populations from Usu mud volcanoes under different temperatures in Xinjiang.Soil samples in mud volcanoes were isolated using ISP5 isolation media containing 10% NaCl with dilution-plate method. To do cultivable moderately halophilic microbial communities diversity and biogeography analysis for 4 sampling sites, isolates were selected for phylogenetic analysis and BOX-PCR genomic DNA fingerprinting analysis. A total of 50 moderate halophilic bacteria and actinomycetes were obtained in our study. Thirty had their unique 16S rDNA genotype, twenty were considered as nine 16S rDNA overlapping genotypes. Thirteen isolates were found belonging to 7 genus and Nesterenkonia were prevailed in sample 1. Nine were found belonging to 5 genus and Halomonas were predominated in sample 2. Thirteen were found belonging to 6 genus, Halomonas and Marinobacter were dominated in sample 3. Fifteen were found belonging to 7 genus and Halomonas were typical in sample 4. The BOX-PCR and cluster analysis showed that there were four strains with two overlapping genotypes among the twenty 16S rDNA genotype overlapped strains. The results indicate that there are differences in microbial community diversity among geographic barrier isolated sampling sites. There are also the endemic distribution of halophilic bacterial and actinobacterial microbes from four mud volcanoes in Xinjiang.The T-RFLP technique was used to study the bacterial and archaeal diversities of four samples. Each T-RFLP profiles were subjected to a combined correlation analysis and principal components analysis, in order to know the relationships among microbial community diversity, linearity geographic distance and environmental factors. The results indicate that bacterial diversities are related with the concentrations of Ca2+, CO32-, HCO3-, Cl- and K+, but irrelative with geographic distance between sites. Archaeal diversities are affected by latitude, temperature and linearity geographic distance and altitude.In order to study the r-K strategy microbial populations from Usu mud volcanoes under different temperatures in Xinjiang, samples (sample 1, 25℃and sample 5, 16℃) were tested by colony-formation curve analyses , 16S rDNA gene phylogenetic analyses and the r-K strategy theory. The composition or the numbers of r-K communities were different between two samples and the number of K- strategists was higher than r- strategists. Results indicate that mud volcanoes cultivate bacterial ecological strategies were generally varied with the environment temperature and nutrient condition. However, the facultative oligotrophic bacteria behaved unique, some with a steady ecology strategy, while others were r-K continuum of strategies.