College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China;State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology;State Key Laboratory of Ocean Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
2.
State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology;State Key Laboratory of Ocean Engineering, Shanghai Jiao Tong University, Shanghai 200240, China;School of System Biology, Shanghai Jiao Tong University, Shanghai 200240, China
3.
State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology;State Key Laboratory of Ocean Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
4.
State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology
Members of Thermococcales are organoheterotrophic hyperthermophilic anaerobes consisting of three genera, Thermococcus, Pyrococcus, and Palaeococcus, among which Thermococcus are the most frequently isolated. In this study, a variety of Thermococcales strains were isolated from the Guaymas Basin hydrothermal vents under different temperatures and pressures. Based on their 16S rRNA gene sequences, all the strains isolated from 85℃ or 95℃ enrichment cultures at ambient pressure were classified as Thermococcus, while strains isolated from 108℃-30MPa enrichment cultures belonged to Pyrococcus. The combination of high pressure and high temperature for enrichment was shown to be an efficient method for isolating Pyrococcus strains. Through selecting and analyzing with multiple molecular phylogenetic markers, the isolated Thermococcales strains were found quite diversified including several putative novel species. This demonstrates a vast genetic reservoir of Thermoccoccales in the deep-sea hydrothermal vents, and a fast evolving of the Thermococcales species adapting to the fast changing environment.
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