Pseudonocardia spinosispora sp. nov., isolated from Korean soil

A new strain of the genus Pseudonocardia, which was isolated from a Korean soil sample, is described. The organism shows distinct cultural characteristics in that it forms well-developed aerial mycelium that fragments into rod-shaped, spiny spores, and grows only in standing culture but not in shake culture. Substrate mycelium is sparse or absent in most media used. Phylogenetic analyses based on 16S rDNA sequences reveal that this isolate forms a distinct clade within the radiation encompassing the genera Pseudonocardia and Actinobispora of the family Pseudonocardiaceae. The affiliation to the genus Pseudonocardia is also supported by the cell chemistry, which is represented by the presence of meso-diaminopimelic acid, arabinose and galactose in the cell wall, tetrahydrogenated menaquinone with eight isoprene units as a predominant menaquinone, and phosphatidylcholine as a diagnostic phospholipid. The levels of 16S rDNA sequence similarity found between the isolate and the type strain of validly described species in the genus Pseudonocardia ranged from 94.8 to 96.3%. The organism is also readily differentiated from all of the validated species of the genus Pseudonocardia by means of a battery of phenotypic tests. The name proposed for the new species is Pseudonocardia spinosispora sp. nov. The type strain is LM 141T (= IMSNU 50581T = KCTC 9991T = NRRL B-24156T).