Kineococcus rhizosphaerae sp. nov., isolated from rhizosphere soil

Abstract

An orange-coloured actinomycete, designated strain RP-B16T, was isolated from a rhizosphere soil. Cells of strain RP-B16T were strictly aerobic, Gram-positive-staining, oxidase-negative, catalase-positive, motile cocci. A phylogenetic tree, based on 16S rRNA gene sequences, showed that members of the genus Kineococcus were divided into two independent clusters and that strain RP-B16T formed a coherent clade with the type strains of Kineococcus aurantiacus (99.5% sequence similarity) and Kineococcus radiotolerans (99.1%). Levels of 16S rRNA gene sequence similarity between strain RP-B16T and Kineococcus marinus KST3-3T and 'Kineococcus tegulae' T2A-S27 were lower than 97.0%. Chemotaxonomic characteristics were typical of the genus Kineococcus in having meso-diaminopimelic acid as the diagnostic diamino acid, MK-9(H2) as the predominant menaquinone, a polar lipid profile comprising diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and two unknown phospholipids, anteiso-C15:0 as the predominant fatty acid and a DNA G+C content of 73.8 mol%. Strain RP-B16T showed levels of DNA-DNA relatedness of 34.6-37.3% to Kineococcus aurantiacus DSM 7487T and 31.2-32.7% to Kineococcus radiotolerans DSM 14245T. On the basis of phenotypic features and DNA-DNA hybridization data, strain RP-B16T is considered to represent a novel species of the genus Kineococcus, for which the name Kineococcus rhizosphaerae sp. nov. is proposed. The type strain is RP-B16T (=KCTC 19366T=DSM 19711T).