Subtercola vilae sp. nov., a novel actinobacterium from an extremely high-altitude cold volcano lake in Chile

A novel actinobacterium, strain DB165^T, was isolated from cold waters of Llullaillaco Volcano Lake (6170 m asl) in Chile. Phylogenetic analysis based on 16S rRNA gene sequences identified strain DB165^T as belonging to the genus Subtercola in the family Microbacteriaceae, sharing 97.4% of sequence similarity with Subtercola frigoramans DSM 13057^T, 96.7% with Subtercola lobariae DSM 103962^T, and 96.1% with Subtercola boreus DSM 13056^T. The cells were observed to be Gram-positive, form rods with irregular morphology, and to grow best at 10-15 °C, pH 7 and in the absence of NaCl. The cross-linkage between the amino acids in its peptidoglycan is type B2γ; 2,4-diaminobutyric acid is the diagnostic diamino acid; the major respiratory quinones are MK-9 and MK-10; and the polar lipids consist of phosphatidylglycerol, diphosphatidylglycerol, 5 glycolipids, 2 phospholipids and 5 additional polar lipids. The fatty acid profile of DB165^T (5% >) contains iso-C14:0, iso-C16:0, anteiso-C15:0, anteiso-C17:0, and the dimethylacetal iso-C16:0 DMA. The genomic DNA G+C content of strain DB165^T was determined to be 65 mol%. Based on the phylogenetic, phenotypic, and chemotaxonomic analyses presented in this study, strain DB165^T (= DSM 105013^T = JCM 32044^T) represents a new species in the genus Subtercola, for which the name Subtercola vilae sp. nov. is proposed.