Polymorphobacter fuscus sp. nov., isolated from permafrost soil, and emended description of the genus Polymorphobacter

Abstract

Strain D40PT, representing a novel Gram-stain-negative, obligately aerobic, bacteriochlorophyll a-containing bacterium of the α-4 subgroup of the phylum Proteobacteria, was isolated from permafrost soil of Kunlun mountains gap, Qinghai-Tibet plateau. Cells were non-motile rod–cocci and formed brown-pigmented colonies. According to the absorption spectrum, carotenoids and two different photosynthetic light-harvesting complexes, an LHI complex and a B800-835-type peripheral LHII complex, were present in the cells. The strain was oxidase-negative and catalase-positive. The predominant fatty acids of strain D40PT were summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), C17 : 1ω6c and summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c). The main polar lipids were phosphatidylethanolamine, phosphatidylglycerol, unidentified phospholipid, two glycolipids and sphingoglycolipid. The major respiratory quinone was ubiquinone-10, whereas ubiquinone-9 was present in smaller amounts. The 16S rRNA gene sequence similarity to the closest phylogenetic relative, Polymorphobacter multimanifer JCM 18140T, was 97.5 %. DNA–DNA relatedness (ΔT m) between strain D40PT and P. multimanifer was 12.4 °C. The G+C content of the genomic DNA of strain D40PT was 67.4 mol%. Accordingly, the strain represents a novel species, for which the name Polymorphobacter fuscus sp. nov. is proposed. The type strain is D40PT ( = CGMCC 1.12714T = JCM 19740T). An emended description of the genus Polymorphobacter is also proposed.