sp. nov., isolated from deep-sea sediment of the Mariana Trench.

Two novel Gram-stain-negative, facultative anaerobic, non-flagellated, rod-shaped bacterial strains, designated MT13 and MT32, were isolated from sediment samples collected from the Mariana Trench at a depth of 8300 m. The two strains grew at -2-30 °C (optimum, 25 °C), at pH 5.5-10.0 (optimum, pH 7.5-8.0) and with 0-15 % (w/v) NaCl (optimum, 3-6 %). They did not reduce nitrate to nitrite nor hydrolyse Tweens 40 and 80, aesculin, casein, starch and DNA. The genomic G+C contents of draft genomes of strain MT13 and MT32 were 52.2 and 54.1 m ol%, respectively. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strains MT13 and MT32 were affiliated with the genus , with the highest similarity to the type strain of . The values of average nucleotide identity and DNA-DNA hybridization between strain MT13 and MT32, and between strain MT13 and five closely related type strains of species indicated that strains MT13 and MT32 belonged to the same species, but represented a novel species in the genus of . The major cellular fatty acids of strains MT13 and MT32 were C, summed feature 3(C 7/6) and summed feature 8 (C 7/6). Major polar lipids of strains MT13 and MT32 included phosphatidylglycerol, phosphatidylethanolamine and diphosphatidylglycerol. Ubiquinone-9 was the predominant respiratory quinone. Based on data from the present polyphasic study, strains MT13 and MT32 represent a novel species of the genus , for which the name sp. nov. is proposed. The type strain is MT13 (=MCCC 1K06389=KCTC 82923).