| The order Thermococcales represents a large group of hyperthermophilic organoheterotrophic anaerobes. It consists of three genera, Thermcococcus, Pyrococcus, Palaeococcus. They are widely distributed in various marine high temperature solfataric environments as one of the dominant microbial groups. As a group of sulfur reducers, they play an important role in the carbon and sulfur circulation in various ecosystems. They are located at the root of 16s rRNA-based phylogenetic tree, suggesting they are ancestors of early life. Guaymas Basin is located on the east pacific, has high temperature vent fluid and full of petroleum like products. Thermococcus. LMO09A501 is a hyperthermophilic and barophilic anaerobes, which is isolated from Guaymas Basin. Its grow temperature range from 65-114℃, growth pressure from 0.1-40 MPa. It grows well under pH between 5.0 and 9.0, with concentration of NaCl from 1.0-5.0%. When sulfur is added in the medium,we can analysis the metabolic gas with H2S, CO2, H2. Thermococcus sp. LMO09A501 is an organoheterotrophic strain, which can used a large mount of organics as carbon and nitrogen source, such as peptone, yeast extract, beef extract, amino acids and so on. It is distanit from Thermococcus, as it can widely use sulfate, thiosulfate, nitrate as electron acceptors, except for sulfate.Genome documented the evolution history of microorganisms and their adaptation to special environment. This study determined and annotated the complete 2124073bp genome of LMO09A501, followed by a comparison with other three Thermococcus genomes. Analysis also found the gene order of LMO09A501 genome was completely different from other Thermococcus. And these differences are caused by Crispr sequences in the genome. Comparative genome analysis reveals this order has common genes and unique genes among other four Thermococcus. The common genes cover the metabolic pathways, such as EM, AA, energy metabolism and carbon fixation.Gene function analysis reveals Thermococcus. LMO09A501 can use a wide range of complex organics, such as disaccharide and polysaccharide. This order also has a lot of membrane complex, hydrogenases and a set of formate lysis system, suggesting that it can acquire energy in the extreme environment. We also find the genes involved in carbon fixation pathway, providing hydrocarbon when there is not enough carbon source. This finding maybe a fact of adaption to the environment. |
