Blastococcus montanus sp. nov., a multi-stress-resistant and bacteriostatic-producing bacterium isolated from the Flaming Mountain, Xinjiang,China

A bacterial strain designated HT6-4^T was isolated from soil samples collected from the Flaming Mountain, Xinjiang, PR China. The purpose of this study was to describe a novel species and its characteristics, through genome sequencing and analysis of the relationship between the members of the genus <i>Blastococcus</i>, and explore the antiradiation, antioxidation and antibacterial capabilities of strain HT6-4^T. The polyphasic study confirmed the affiliation of strain HT6-4^T with the genus <i>Blastococcus</i>. Strain HT6-4^T was aerobic, Gram-stain-positive, non-budding, non-motile, catalase-positive and oxidase-negative. It grew at 10-37 °C, pH 5.0-8.0 and 0-4% (w/v) NaCl. Colonies were circular, smooth and bright orange in colour. In addition, strain HT6-4^T was drought tolerant. The predominant menaquinone was MK-9, with MK-8 as the minor component. The polar lipids of strain HT6-4^T were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, phosphatidylinositol, phospholipids, an unidentified aminolipid and two unidentified phospholipids. Whole-cell hydrolysates contain <i>meso</i>-diaminopimelic acid as the diagnostic diamino acid and ribose and galactose as diagnostic sugars. Its major fatty acids were iso-C_{16 : 0}, C_{17 : 1} <i>ω</i>8<i>c</i> and C_{18 : 1} <i>ω</i>9<i>c</i>. The genome of strain HT6-4^T was 4.30 Mb in the whole-genome shotgun project. The G+C content was 73.9 mol%. The phylogenetic analysis based on the 16S rRNA gene sequence showed that strain HT6-4^T was closely related to <i>Blastococcus jejuensis</i> KST3-10^T(97.9%), <i>Blastococcus capsensis</i> BMG 804^T(97.8%), <i>Bl</i>astococcus <i>aggregatus</i> DSM 4725^T(97.5%), <i>Blastococcus saxobsidens</i> BC 444^T(97.5%), <i>Blastococcus xanthinilyticus</i> BMG 862^T(97.5%) and <i>Blastococcus litoris</i> GP-S2-8^T(97.5%). The average nucleotide identity (OrthoANI) and digital DNA-DNA hybridization (dDDH) values among strain HT6-4^T and <i>B. jejuensis</i> KST3-10^T, <i>B. capsensis</i> BMG 804^T, <i>B. aggregatus</i> DSM 4725^T, <i>B. saxobsidens</i> BC 444^T, <i>B. xanthinilyticus</i> BMG 862^T and <i>B. litoris</i> GP-S2-8^T were below the species delimitation thresholds. The genome of strain HT6-4^T contained antiradiation genes, antioxidant genes and antibacterial genes. Based on its morphological, physiological and chemical taxonomic characteristics, strain HT6-4^T (=KCTC 59234^T =GDMCC 1.4386^T) should be classified as a novel species of the genus <i>Bl</i>astococcus with the proposed name <i>Blastococcus montanus</i> sp. nov.