Nocardioides iriomotensis sp. nov., an actinobacterium isolated from forest soil

Abstract

An actinomycete strain, designated IR27-S3T, was isolated from a forest soil sample collected from Iriomote Island, Okinawa, Japan. Cells of the isolate were Gram-stain-positive, aerobic, non-sporulating, non-motile coccoids or short rods. The strain grew in the presence of 0–7 % (w/v) NaCl, at pH 6–8 and at 12–37 °C, with optimum growth at 30 °C. Chemotaxonomically, the strain contained ll-diaminopimelic acid as the diagnostic diamino acid and MK-8(H4) as the predominant menaquinone. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and an unknown phospholipid. The major cellular fatty acids were iso-C16 : 0, C17 : 1 cis-9, C15 : 0 and iso-C15 : 0. The DNA G+C content was 73.7 mol%. On the basis of 16S rRNA gene sequence analysis, strain IR27-S3T was closely related to Nocardioides mesophilus MSL-22T (98.1 % 16S rRNA gene sequence similarity), Marmoricola bigeumensis MSL-05T (97.2 %) and Nocardioides jensenii DSM 20641T (96.5 %). On the basis of fatty acid analysis, phylogenetic analysis and phenotypic data, the isolate should be classified in a novel species of the genus Nocardioides, for which the name Nocardioides iriomotensis sp. nov. is proposed. The type strain is IR27-S3T ( = NBRC 105384T  = KACC 14926T).