Phylogenetic Analysis of Psychrophilic Bacteria in Arctic Deep Sea Sediment

A total of 19 psychrophilic bacteria were isolated from deep sea sediment of Bering Sea,Arctic.The identification and phylogenetic analysis of these psychrophiles were carried out based on the comparison of 16S rDNA gene sequences.The phylogenetic relationship was compared among the psychrophiles isolated from deep sea sediment of Arctic and the tropical western Pacific warm pool area.The results showed that most of the arctic psychrophilic bacteria belonged to γ-proteobacteria,and the rest belonged to α-proteobacteria and gram-positive bacteria.The dominant genera of these bacteria were Pseudoalteromonas,Pseudomonas and Shewanella that belonged to γ-proteobacteria.Comparing with the psychrophilic bacteria isolated from the sediment of tropical western Pacific,Pseudoalteromonas and Pseudomonas were two universal genera in these two sea area,while the genus Shewanella only isolated from the Arctic Ocean.The phylogenetic analysis indicated that the psychrophilic bacteria isolated from sediment of Arctic and the western Pacific were located in the independent clade separately,some of them constitute an individual clade completely.These results possible suggested that the habitation and evolution of psychrophilic bacteria were affected by the environment.