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

Abstract

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 Blastococcus, 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 Blastococcus. 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 meso-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} ω8c and C_{18 :  1} ω9c. 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 Blastococcus jejuensis KST3-10^T(97.9%), Blastococcus capsensis BMG 804^T(97.8%), Blastococcus aggregatus DSM 4725^T(97.5%), Blastococcus saxobsidens BC 444^T(97.5%), Blastococcus xanthinilyticus BMG 862^T(97.5%) and Blastococcus litoris GP-S2-8^T(97.5%). The average nucleotide identity (OrthoANI) and digital DNA-DNA hybridization (dDDH) values among strain HT6-4^T and B. jejuensis KST3-10^T, B. capsensis BMG 804^T, B. aggregatus DSM 4725^T, B. saxobsidens BC 444^T, B. xanthinilyticus BMG 862^T and B. litoris 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 Blastococcus with the proposed name Blastococcus montanus sp. nov.