Nocardia rayongensis sp. nov., isolated from Thai peat swamp forest soil

An actinomycete strain, RY45-3T, isolated from a peat swamp forest soil in Rayong Province, Thailand, was characterized using a polyphasic approach. The strain belonged to the genus Nocardia on the basis of morphological, physiological, biochemical and chemotaxonomic properties. Cell-wall peptidoglycan contained meso-diaminopimelic acid. The N-acyl group of muramic acid in the cell wall was glycolyl type. The diagnostic sugars in whole-cell hydrolysates were galactose and arabinose. MK-8 (H4ω-cycl) was the major menaquinone. The major fatty acids were C16 : 0 and C18 : 1ω9c. The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannosides. The genomic DNA G+C content was 71 mol%. On the basis of 16S rRNA gene sequence similarity analysis, strain RY45-3T was closely related to Nocardia jiangxiensis JCM 12861T (98.9 %), Nocardia nova JCM 6044T (98.8 %) and Nocardia pseudobrasiliensis JCM 9894T (98.6 %). The strain showed low levels of DNA-DNA relatedness with N. jiangxiensis JCM 12861T, N. nova JCM 6044T and N. pseudobrasiliensis JCM 9894T (range from 3.6 to 55.3 %). On the basis of the phenotypic characteristics and the results mentioned, this strain could be differentiated from closely related type strains and represents a novel species of the genus Nocardia, for which the name Nocardia rayongensis sp. nov. (type strain RY45-3T = JCM 19832T = TISTR 2213T = PCU 334T) is proposed.