Thermococcus indicus sp. nov., a Fe(III)-reducing hyperthermophilic archaeon isolated from the Onnuri Vent Field of the Central Indian Ocean ridge

• Published in: The journal of microbiology 2020, 58(4), , pp.260-267
• Main Authors: Lim, Jae Kyu, Kim, Yun Jae, Yang, Jhung-Ahn, Namirimu, Teddy, Yang, Sung-Hyun, Park, Mi-Jeong, Kwon, Yong Min, Lee, Hyun Sook, Kang, Sung Gyun, Lee, Jung-Hyun, Kwon, Kae Kyoung
• Format: Article
• Language: English
• Subjects: Biomedical and Life Sciences; Carbon sources; Chromosomes; Citric acid; Deep sea; Deep water; Deoxyribonucleic acid; DNA; Flagella; Genes; Genomes; Hydrothermal plumes; Iron; Life Sciences; Maltodextrin; Maltose; Microbial Systematics and Evolutionary Microbiology; Microbiology; New species; Nucleotide sequence; pH effects; Phylogeny; Plasmids; Pyruvic acid; rRNA 16S; Sequencing; Similarity; Sodium chloride; Starch; Sulfur; Sulphur; 생물학
• ISSN: 1225-8873; 1976-3794
• DOI: 10.1007/s12275-020-9424-9

A strictly anaerobic, dissimilatory Fe(III)-reducing hyperthermophilic archaeon, designated as strain IOH1 T , was isolated from a new deep-sea hydrothermal vent (Onnuri Vent Field) area in the Central Indian Ocean ridge. Strain IOH1 T showed > 99% 16S rRNA gene sequence similarity with Thermococcus celericrescens TS2 T (99.4%) and T. siculi DSM 12349 T (99.2%). Additional three species T. barossii SHCK-94 T (99.0%), T. celer Vu13 T (98.8%), and T. piezophilus (98.6%) showed > 98.6% of 16S rRNA gene sequence similarity, however, the maximum OrthoANI value is 89.8% for the genome of T. celericrescens TS2 T . Strain IOH1 T cells are coccoid, 1.2–1.8 μm in diameter, and motile by flagella. Growth was at 70–82°C (optimum 80°C), pH 5.4–8.0 (optimum pH 6.0) with 2–4% (optimum 3%) NaCl. Growth of strain IOH1T was enhanced by starch, pyruvate, D(+)-maltose and maltodextrin as a carbon sources, and elemental sulfur as an electron acceptor; clearly different from those of related species T. celecrescens DSM 17994 T and T. siculi DSM 12349 T . Strain IOH1 T , T. celercrescence DSM 17994 T , and T. siculi DSM 12349 T reduced soluble Fe(III)-citrate present in the medium, whereas the amount of total cellular proteins increased with the concomitant accumulation of Fe(II). We determined a circular chromosome of 2,234 kb with an extra-chromosomal archaeal plasmid, pTI1, of 7.7 kb and predicted 2,425 genes. The DNA G + C content was 54.9 mol%. Based on physiological properties, phylogenetic, and genome analysis, we proposed that strain IOH1 T (= KCTC 15844 T = JCM 39077 T ) is assigned to a new species in the genus Thermococcus and named Thermococcus indicus sp. nov.