Antiquaquibacter oligotrophicus gen. nov., sp. nov., a novel oligotrophic bacterium from groundwater

Abstract

In this study, a Gram-stain-positive, non-motile, oxidase- and catalase-negative, rod-shaped, bacterial strain (SG_E_30_P1T) that formed light yellow colonies was isolated from a groundwater sample of Sztaravoda spring, Hungary. Based on 16S rRNA phylogenetic and phylogenomic analyses, the strain was found to form a distinct linage within the family Microbacteriaceae . Its closest relatives in terms of near full-length 16S rRNA gene sequences are Salinibacterium hongtaonis MH299814 (97.72 % sequence similarity) and Leifsonia psychrotolerans GQ406810 (97.57 %). The novel strain grows optimally at 20–28 °C, at neutral pH and in the presence of NaCl (1–2 w/v%). Strain SG_E_30_P1T contains MK-7 and B-type peptidoglycan with diaminobutyrate as the diagnostic amino acid. The major cellular fatty acids are anteiso-C15 : 0, iso-C16 : 0 and iso-C14 : 0, and the polar lipid profile is composed of diphosphatidylglycerol and phosphatidylglycerol, as well as an unidentified aminoglycolipid, aminophospholipid and some unidentified phospholipids. The assembled draft genome is a contig with a total length of 2 897 968 bp and a DNA G+C content of 65.5 mol%. Amino acid identity values with it closest relatives with sequenced genomes of <62.54 %, as well as other genome distance results, indicate that this bacterium represents a novel genus within the family Microbacteriaceae . We suggest that SG_E_30_P1T (=DSM 111415T=NCAIM B.02656T) represents the type strain of a novel genus and species for which the name Antiquaquibacter oligotrophicus gen. nov., sp. nov. is proposed.