Pontibacter arcticus sp. nov., isolated from rhizosphere soil of Saxifraga oppositifolia.

Abstract

A Gram-stain-negative, rod-shaped, red-coloured and aerobic bacterium, designated 2b14T, was isolated from rhizosphere soil of Saxifraga oppositifolia sampled at the Chinese Arctic Yellow River Station in Norway. Optimal growth occurred at 28 °C (range, 4-37 °C) and pH 7.0-7.5 (pH 6.5-8.5). The strain could tolerate up to 2.5 % (w/v) NaCl concentration. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain 2b14Thad the highest similarity value of 96.0 % to Pontibacter diazotrophicus CCTCC AB 2013049T. The major fatty acids were summed feature 4 (anteiso-C17 : 1 B and/or iso-C17 : 1 I), iso-C15 : 0 and iso-C17 : 0 3-OH. The major polar lipid was found to be phosphatidylethanolamine. The genomic DNA G+C content of strain 2b14T was 45.5 mol%. The sole respiratory quinone was MK-7. The combined results of physiological, genotypic, phylogenetic and chemotaxonomic analyses showed that strain 2b14T represents a novel species within the genus Pontibacter, for which the name Pontibacter arcticus sp. nov. is proposed. The type strain is 2b14T (=KCTC 62596T=MCCC 1H00304T).