Thermococcus onnurineus NA1: a Lithoheterotroph as Revealed by Genome Analysis

Abstract

A Lithoheterotroph pathway of hyperthermophilic marine archaea Thermococcus onnurineus was revealed by Genome Analysis. To provide some insight into factors that contributed to the apparent successful competition of Thermococcus spp. in hydrothermal vent fields, the genome sequence of T. onnurineus NA1 was determined by combining random whole-genome shotgun sequencing with pyrosequencing. As a result, it was revealed that T. onnurineus NA1 has a single circular chromosome (1,847,607 bp) without any exochromosomal elemnets, and a total of 1,976 coding DNA sequences (CDSs) were identified. Synteny comparison by blastp-all-va-all between T. onnurineus NA1 and other Thermococcales strains confirmed the high frequency of DNA rearrangement. The gene rearrangement between T.onnurineus NA1 and T. kodakaraensis KOD1 seemed to take place at the level of chromosomal segments, confirming more close phylogenetic relationship than to other Pyrococcus strains. Interestingly, we found that T. onnurineus NA1 retained the metabolic pathways not only for organotrophic growth but also for lithotrophic growth by analyzing the genome sequence.