Pseudoxanthomonas koreensis sp nov and Pseudoxanthomonas daejeonensis sp nov.

Abstract

Gram-negative, non-spore-forming, rod-shaped bacteria, T7-09(T) and TR6-08(T), 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 T7-09(T) and TR6-08(T) were shown to belong to the Proteobacteria and showed the highest levels of sequence similarity to Pseudoxanthomonas broegbernensis DSM 12573(T) (98-1%), Pseudoxanthomonas mexicana AMX 26B(T) (97-4-97.5%), Pseudoxanthomonas japonensis 12-3(T) (96-5-96-6%), Pseudoxanthomonas taiwanensis ATCC BAA-404(T) (95.7 %) and Xanthomonas campestris ATCC 33913(T) (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 C-17:1 iso omega 9c and by their unique biochemical profiles. The results of DNA-DNA hybridization clearly demonstrated that T7-09(T) and TIR6-08(T) represent separate species. On the basis of these data, it is proposed that T7-09(T) (= KCTC 12208(T) = lAM 15116(T)) and TR6-08(T) (=KCTC 12207(T) = IAM 15115(T)) 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.