Saxibacter everestensis gen. nov., sp. nov., A Novel Member of the Family Brevibacteriaceae, Isolated from the North Slope of Mount Everest.

Abstract

We isolated and analyzed a novel, Gram-stain-positive, aerobic, rod-shaped, non-motile actinobacterium, designated as strain ZFBP1038^T, from rock sampled on the north slope of Mount Everest. The growth requirements of this strain were 10-37 °C, pH 4-10, and 0-6% (w/v) NaCl. The sole respiratory quinone was MK-9, and the major fatty acids were anteiso-C_15:0 and iso-C_17:0. Peptidoglycan containing meso-diaminopimelic acid, ribose, and glucose were the major cell wall sugars, while polar lipids included diphosphatidyl glycerol, phosphatidyl glycerol, an unidentified phospholipid, and an unidentified glycolipid. A phylogenetic analysis based on 16S rRNA gene sequences showed that strain ZFBP1038^T has the highest similarity with Spelaeicoccus albus DSM 26341 ^T (96.02%). ZFBP1038^T formed a distinct monophyletic clade within the family Brevibacteriaceae and was distantly related to the genus Spelaeicoccus. The G + C content of strain ZFBP1038^T was 63.65 mol% and the genome size was 4.05 Mb. Digital DNA-DNA hybridization, average nucleotide identity, and average amino acid identity values between the genomes of strain ZFBP1038^T and representative reference strains were 19.3-25.2, 68.0-71.0, and 52.8-60.1%, respectively. Phylogenetic, phenotypic, and chemotaxonomic characteristics as well as comparative genome analyses suggested that strain ZFBP1038^T represents a novel species of a new genus, for which the name Saxibacter gen. nov., sp. nov. was assigned with the type strain Saxibacter everestensis ZFBP1038^T (= EE 014 ^T = GDMCC 1.3024 ^T = JCM 35335 ^T).