Nocardia speluncae sp. nov., isolated from a cave.

The taxonomic status of a mycolic acid-containing actinomycete, isolated from a natural cave on Jeju Island, Republic of Korea, was investigated by means of a polyphasic approach. The isolate, designated strain N2-11(T), produced yellow- to orange-coloured vegetative hyphae and white- to pinkish white-coloured aerial mycelia, both of which fragmented into irregular rod-shaped elements. Phylogenetic analyses based on 16S rRNA gene sequences revealed that the organism belonged to the family Nocardiaceae, occupying a distinct position between Nocardia harenae and a Nocardia carnea cluster. The results of chemotaxonomic analyses were consistent with the affiliation of the organism with the genus Nocardia. On the basis of 16S rRNA gene sequence similarities, the closest phylogenetic neighbours were the type strains of N. carnea (98.3 %), Nocardia flavorosea (98.0 %), Nocardia sienata (97.9 %) and Nocardia testacea (97.8 %), but the organism could be clearly distinguished from its phylogenetic relatives with reference to a broad range of physiological markers. On the basis of phenotypic and molecular genetic data presented in this study, strain N2-11(T) represents a novel species of the genus Nocardia, for which the name Nocardia speluncae sp. nov. is proposed. The type strain is N2-11(T) (=JBRI 2006(T) =KCTC 19223(T) =DSM 45078(T)).