Caulobacter soli sp. nov., isolated from soil sampled at Jiri Mountain, Republic of Korea

Abstract

A Gram-stain-negative, yellow-pigmented, aerobic, non-spore-forming, motile with a single polar flagellum and rod-shaped bacterium, Ji-3-8T, was isolated from a soil sample taken from Jiri Mountain, Republic of Korea. Comparative 16S rRNA gene sequence studies showed the isolate had clear affiliation with Alphaproteobacteria and the closest relatedness to Caulobacter rhizosphaerae KCTC 52515T, Caulobacter henricii ATCC 15253T, Caulobacter segnis ATCC 21756T, Caulobacter hibisci THG-AG3.4T, Caulobacter flavus RHGG3T and Caulobacter vibrioides CB51T showing 99.1, 98.9, 97.7, 97.6, 97.5 and 97.4 % 16S rRNA gene sequence similarity, respectively, and 94.7–96.5 % to the remaining species of genus Caulobacter . The predominant ubiquinone was Q-10 and the major fatty acids were C18 : 1  ω7c 11-methyl, C16 : 0, summed feature 8 (C18 : 1  ω6c and/or C18 : 1  ω7c) and summed feature 3 (C16 : 1  ω6c and/or C16 : 1  ω7c). The major polar lipids were found to be phosphatidylglycerol, two unidentified phosphoglycolipid and two unidentified glycolipids. The G+C content of the genomic DNA of strain Ji-3-8T was 68.1 mol%. Average nucleotide identity and digital DNA–DNA hybridization values of strain Ji-3-8T with C. rhizosphaerae KCTC 52515T, C. henricii ATCC 15253T, C. segnis ATCC 21756T, C. flavus RHGG3T and C. vibrioides were 79.7–87.7% and 23.0–34.3%, respectively. Based on the polyphasic evidence, it is proposed that strain Ji-3-8T forms a novel species in the genus Caulobacter , for which the name Caulobacter soli sp. nov. is proposed. The type strain is Ji-3-8T (=CCTCC AB 2019389T=KCTC 72990T).