Nocardioides kribbensis sp. nov., isolated from an alkaline soil

Abstract

Three Gram-positive, rod- or coccoid-shaped bacterial strains, KSL-2T, KSL-5 and KSL-6, were isolated from an alkaline soil in Korea and subjected to a polyphasic taxonomical analysis. These isolates grew optimally at pH 9·0 and 30 °C. They were characterized chemotaxonomically as having cell wall peptidoglycan based on ll-2,6-diaminopimelic acid, MK-8(H4) as the predominant menaquinone and iso-C16 : 0 as the major fatty acid. The DNA G+C content of the isolates was 73–74 mol%. Strains KSL-2T, KSL-5 and KSL-6 were identical in their 16S rRNA gene sequences and exhibited DNA–DNA relatedness values of 88–93 %. Phylogenetic trees based on 16S rRNA gene sequences showed that the three isolates fell within the evolutionary radiation encompassed by the genus Nocardioides. Levels of 16S rRNA gene sequence similarity between the three strains and the type strains of Nocardioides species ranged from 93·6 % (with Nocardioides albus) to 97·2 % (with Nocardioides aquiterrae). DNA–DNA relatedness levels between the three isolates and N. aquiterrae CJ-14T were 8–15 %. On the basis of phenotypic, phylogenetic and genetic data, strains KSL-2T, KSL-5 and KSL-6 were classified in the genus Nocardioides as members of a novel species for which the name Nocardioides kribbensis sp. nov. is proposed, with KSL-2T (=KCTC 19038T=DSM 16314T) as the type strain.