Description and genomic characterization of Aquipuribacter aurantiacus sp. nov., isolated from saline lake sediment.

Abstract

Strains MA13-6T and MA13-13, two Gram-stain-positive, aerobic, short rod-shaped actinobacteria, were isolated from a saline lake in Ngari Prefecture, Xizang Autonomous Region, China. Phylogenetic analysis based on 16S rRNA gene sequences indicated that these two strains belonged to the genus Aquipuribacter, with the closest relationship to Aquipuribacter hungaricus IV-75T (98.47% sequence similarity) and Aquipuribacter nitratireducens AMV4T (97.36% sequence similarity). Phylogenetic analysis based on genomes further confirmed their classification as a distinct cluster within the genus Aquipuribacter. The average nucleotide identity and digtal DNA-DNA hybridization values between these two strains and their closest relative Aquipuribacter hungaricus IV-75T, were 82.44-82.49% and 23.00%, respectively, clearly indicating that strains MA13-6T and MA13-13 represent a novel species. The 16S rRNA gene sequence similarity, average nucleotide identity and digital DNA-DNA hybridization values between these two strains were 99.79%, 99.97% and 99.40%, respectively, unequivocally confirming their classification within the same species. However, DNA fingerprinting analysis distinguished them as non-clonal variants. The polar lipids comprised phosphatidylglycerol, two unidentified phospholipids, two unidentified glycolipids, and two unidentified lipids. The predominant respiratory quinone was MK-10 (H4). The major fatty acids were anteiso-C15:0, C18:1ω9c, isoC16:0 and anteiso-C17:0. The cell wall diagnostic diamino acid was meso-diaminopimelic acid. Based on phylogenetic analyses combined with phenotypic and chemotaxonomic characterization, strains MA13-6T and MA13-13 represent a novel species of the genus Aquipuribacter, for which the name Aquipuribacter aurantiacus sp. nov. is proposed. The type strain is MA13-6T (=MCCC 1K10045T = KCTC 59572T).