[Diversity of culturable bacteria in the typical frozen soil areas in China]

The diversity of culturable bacteria in the six frozen soils from High-latitude area and High-altitude area were analyzed by using culture-dependent approaches.

Three solidified media were used to isolate culturable bacteria. Bacterial 16S rRNA genes of the isolates were PCR amplified using bacteria-universal primers, and then were sequenced. The resulting bacterial 16S rRNA gene sequences were subjected to phylogenetic analysis.

The abundance of culturable bacteria ranged from 4.70 x 10(3) to 2.57 x 10(5) colony forming units (CFU) per gram of soils (dry weight). A total of 144 bacterial strains were obtained. The bacterial isolates from the High-latitude area were affiliated with three phyla (Firmicutes, Gammaproteobacteria, and Betaproteobacteria) with Pseudomonas, Bacillus, and Paenibacillus strains being dominant. The bacterial isolates from High-altitude area could be grouped into three different phyla (Gammaproteobacteria, Firmicutes, and Bacteroidetes) with Pseudomonas strains be dominant.

The culturable bacteria are abundant and diverse in the frozen soils of High-latitude and High-altitude areas. The results also showed that the culturable bacterial community structure varied among different research areas. Our data have implications for a better understanding of culturable bacterial community in the frozen soils in China.