Pseudoxanthomonas koreensis sp. nov. and Pseudoxanthomonas daejeonensis sp. nov.

Abstract

Gram-negative, non-spore-forming, rod-shaped bacteria, T7-09T and TR6-08T, were isolated from soil from a ginseng field in South Korea and characterized to determine their taxonomic position. 16S rRNA gene sequence analysis showed that the two isolates shared 99·5 % sequence similarity. Strains T7-09T and TR6-08T were shown to belong to the Proteobacteria and showed the highest levels of sequence similarity to Pseudoxanthomonas broegbernensis DSM 12573T (98·1 %), Pseudoxanthomonas mexicana AMX 26BT (97·4–97·5 %), Pseudoxanthomonas japonensis 12-3T (96·5–96·6 %), Pseudoxanthomonas taiwanensis ATCC BAA-404T (95·7 %) and Xanthomonas campestris ATCC 33913T (96·3–96·5 %). The sequence similarity values with respect to any species with validly published names in related genera were less than 96·5 %. The detection of a quinone system with Q-8 as the predominant compound and a fatty acid profile with C15 : 0 iso as the predominant acid supported the assignment of the novel isolates to the order ‘Xanthomonadales’. The two isolates could be distinguished from the established species of the genus Pseudoxanthomonas by the presence of quantitative unsaturated fatty acid C17 : 1 iso ω9c and by their unique biochemical profiles. The results of DNA–DNA hybridization clearly demonstrated that T7-09T and TR6-08T represent separate species. On the basis of these data, it is proposed that T7-09T (=KCTC 12208T=IAM 15116T) and TR6-08T (=KCTC 12207T=IAM 15115T) be classified as the type strains of two novel Pseudoxanthomonas species, for which the names Pseudoxanthomonas koreensis sp. nov. and Pseudoxanthomonas daejeonensis sp. nov., respectively, are proposed.