Phenylobacterium glaciei sp. nov., isolated from Vestrebroggerbreen, a valley glacier in Svalbard, Arctic

Abstract

A Gram-stain-negative, rod-shaped bacterial strain designated as 20VBR1T was isolated from a valley glacier (Vestrebroggerbreen) snout ice sample from Ny-Ålesund, Svalbard, Arctic. The colonies were smooth, circular and light creamish on half-strength R2A agar and grew at 10–35 °C (optimum, 20 °C), at pH 6.5–8.0 (optimum, 7.0) and with 0–2.5 % (w/v) NaCl (optimum, 0.5 %). 16S rRNA gene sequence analysis revealed that strain 20VBR1T belonged to the genus Phenylobacterium and was most closely affiliated to Phenylobacterium aquaticum W2-3-4T (97.65 % similarity), Phenylobacterium haematophilum LMG 11050T (97.57 %) and Phenylobacterium koreense Slu-01T (96.91 %). 20VBR1T has a genome size of 4.24 Mb, comprising 4185 predicted genes with a DNA G+C content of 67.86 mol%. DNA–DNA hybridization experiments indicated that the DNA–DNA relatedness between strain 20VBR1T and P. aquaticum KACC 18306T was 41.95±4.36 %, well below the threshold (<70 %) to delineate bacterial species. Genome relatedness indexes revealed that the average nucleotide identity and digital DNA–DNA hybridization values between 20VBR1T and its closest phylogenomic relative, P. aquaticum KACC 18306T, were 78.97 and 22.10 %, respectively. The predominant isoprenoid quinone was ubiquinone (Q-10) and the major polar lipids were phosphatidylglycerol, one unknown phospholipid, one unknown glycolipid and four unidentified polar lipids. The major fatty acids (>10 %) of strain 20VBR1T were summed feature 8 (comprising C18 : 1 ω7c and/or C18 : 1 ω6c), summed feature 3 (comprising C16 : 1 ω6c and/or C16 : 1 ω7c) and C16 : 0. Based on the physiological, biochemical, chemotaxonomic, phylogenetic and phylogenomic analyses, isolate 20VBR1T is considered to represent a novel species of the genus Phenylobacterium , for which the name Phenylobacterium glaciei sp. nov. is proposed. The type strain is 20VBR1T (=JCM 33227 T=DSM 111428 T=MCC 4220 T).