Arthrobacter polaris sp. nov., a new cold-adapted member of the family Micrococcaceae isolated from Antarctic fellfield soil

An aerobic, Gram-stain-positive and non-spore-forming strain, designated C1-1(T), was isolated from a fellfield soil sample collected from frost-sorted polygons on Jane Col, Signy Island, Maritime Antarctic. Cells with a size of 0.65-0.9 x 1.2-1.7 mu m have a flagellar motile apparatus and exhibit a rod-coccus growth cycle. Optimal growth conditions were observed at 15-20 degrees C, pH 7.0 and NaCl concentration up to 0.5 % (w/v) in the medium. The 16S rRNA gene sequence of C1-1(T) showed the highest pairwise similarity of 98.77 % to Arthrobacter glacialis NBRC 113092(T). Phylogenetic trees based on the 16S rRNA and whole-genome sequences revealed that strain C1-1(T) belongs to the genus Arthrobacter and is most closely related to members of the 'Arthrobacter psychrolactophilus group'. The G+C content of genomic DNA was 58.95 mol%. The original and orthologous average nucleotide identities between strain C1-1(T) and A. glacialis NBRC 113092(T) were 77.15 % and 77.38 %, respectively. The digital DNA-DNA relatedness values between strain C1-1(T) and A. glacialis NBRC 113092(T) was 21.6 %. The polar lipid profile was composed mainly of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and an unidentified glycolipid. The predominant cellular fatty acids were anteiso-C-15:0 (75 %) and anteiso-C-17:0 (15.2 %). Menaquinone MK-9(H-2) (86.4 %) was the major respiratory quinone in strain C1-1(T). The peptidoglycan type was determined as A3 alpha (l-Lys-l-Ala(3); A11.6). Based on all described phylogenetic, physiological and chemotaxonomic characteristics, we propose that strain C1-1(T) (=DSM 112353(T)=CCM 9148T) is the type strain of a novel species Arthrobacter polaris sp. nov.

Automated summary

A new species of Arthrobacter, named Arthrobacter polaris, was isolated from a fellfield soil sample collected from frost-sorted polygons on Signy Island in the Maritime Antarctic. The strain exhibited unique characteristics in terms of its morphology, growth conditions, and genetic sequences.