Herbidospora mongoliensis sp. nov., isolated from soil, and reclassification of Herbidospora osyris and Streptosporangium claviforme as synonyms of Herbidospora cretacea.

A Gram-reaction-positive aerobic actinomycete, designated strain MN08-A0118(T), which produced short chains of non-motile spores on the tips of long sporophores and formed yellow-brown colonies with branched substrate mycelium, was studied in detail to determine its taxonomic position. On the basis of 16S rRNA gene sequence analyses, strain MN08-A0118(T) was grouped into the genus Herbidospora, being most closely related to Streptosporangium claviforme (98.2%), Herbidospora osyris (98.2%), Herbidospora daliensis (98.2%), Herbidospora cretacea (97.9%) and Herbidospora yilanensis (97.4%). Chemotaxonomic data supported allocation of the strain to the genus Herbidospora. MK-10(H(4)) was the predominant menaquinone with minor amounts of MK-10(H(6)), MK-10(H(2)) and MK-9(H(4)); the fatty acid profile contained major amounts of iso-C(16:0), C(17:0) 10-methyl, iso-C(14:0) and iso-C(16:0) 2-OH; the phospholipid profile contained phosphatidylethanolamine, phosphatidylmethylethanolamine and glucosamine-containing phospholipids; and the whole-cell sugars included ribose, glucose, galactose, madurose and rhamnose (trace). The phylogenetic data, phenotypic and genotypic properties and DNA-DNA hybridization differentiated this strain from its closely related strains, S. claviforme (35-54% DNA-DNA relatedness), H. osyris (39-51%), H. daliensis (3-16%), H. cretacea (34-39%) and H. yilanensis (34-42%). Thus, MN08-A0118(T) represents a novel species of the genus Herbidospora, for which the name Herbidospora mongoliensis sp. nov. is proposed, with MN08-A0118(T) ( = NBRC 105882(T)  = VTCC D9-22(T)) as the type strain. In addition, DNA-DNA hybridization results showed that S. claviforme and H. osyris are synonyms of H. cretacea.