Alsobacter metallidurans gen. nov., sp. nov., a thallium-tolerant soil bacterium in the order Rhizobiales

Abstract

A thallium-tolerant, aerobic bacterium, designated strain SK200a-9T, isolated from a garden soil sample was characterized using a polyphasic approach. Comparative analysis of 16S rRNA gene sequences revealed that strain SK200a-9T was affiliated with an uncultivated lineage within the Alphaproteobacteria and the nearest cultivated neighbours were bacteria in genera in the family Methylocystaceae (93.3–94.4 % 16S rRNA gene sequence similarity) and the family Beijerinckiaceae (92.3–93.1 %) in the order Rhizobiales . Cells of strain SK200a-9T were Gram-stain-negative, non-motile, non-spore-forming, poly-β-hydroxybutyrate-accumulating rods. The strain was a chemo-organotrophic bacterium, which was incapable of growth on C1 substrates. Catalase and oxidase were positive. Atmospheric nitrogen fixation and nitrate reduction were negative. The strain contained ubiquinone Q-10 and cellular fatty acids C18 : 1ω7c, C18 : 0, C16 : 1ω7c and C16 : 0 as predominant components. The major polar lipids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine and phosphatidylglycerol. The DNA G+C content was 64.8 mol%. On the basis of the information described above, strain SK200a-9T is considered to represent a novel species of a new genus in the order Rhizobiales , for which the name Alsobacter metallidurans gen. nov., sp. nov. is proposed. The type strain of Alsobacter metallidurans is SK200a-9T ( = NBRC 107718T = CGMCC 1.12214T).