Nocardioides cavernae sp. nov., an actinobacterium isolated from a karst cave

A novel actinobacterial strain, designated YIM A1136T, was isolated from a soil sample collected from a karst cave in Xingyi county, Guizhou province, south-western China. The taxonomic position of the strain was investigated using a polyphasic approach. Cells of the strain were aerobic, Gram-staining-positive and rod-shaped. Colonies of the strain were circular, convex, opaque and yellowish-white in colour. On the basis of 16S rRNA gene sequence analysis, strain YIM A1136T was most closely related to the type strains Nocardioides ganghwensis JC2055T (98.3 % sequence similarity), Nocardioides exalbidus RC825T (98.2 %), Nocardioides alpinus Cr7-14T (98.2 %), Nocardioides hwasunensis HFW-21T (98.0 %), Nocardioides oleivorans DSM 16090T (97.9 %) and Nocardioides furvisabuli SBS-26T (97.8 %) and is therefore considered to represent a member of the genus Nocardioides. DNA-DNA hybridization values between strain YIM A1136T and related type strains of the genus Nocardioides were less than 70 %. ll-Diaminopimelic acid was the diagnostic diamino acid in the cell-wall peptidoglycan. The whole-cell sugars were galactose, glucose, mannose, rhamnose and ribose. The major isoprenoid quinone was MK-8(H4), while the major fatty acids (>10 %) were C16 : 0, summed feature 3 and summed feature 8. The polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and two unidentified phospholipids. The genomic DNA G+C content was 71.4 mol%. On the basis of phenotypic, genotypic and phylogenetic data, strain YIM A1136T merits representation of a novel species of the genus Nocardioides, for which the name Nocardioides cavernae sp. nov. is proposed. The type strain is YIM A1136T (=KCTC 39551T=DSM 29950T).