Actinomycetospora atypica sp. nov., a novel soil actinomycete and emended description of the genus Actinomycetospora.

A novel actinomycete, designated strain NEAU-st4(T), was isolated from a soil sample collected from Shaanxi province, Northwest China and characterized using a polyphasic approach. 16S rRNA gene sequence analysis revealed that strain NEAU-st4(T) has the highest sequence similarities with Actinomycetospora rishiriensis RI109-Li102(T) (99.4 %), Actinomycetospora corticicola 014-5(T) (99.1 %), Actinomycetospora chiangmaiensis YIM 0006(T) (98.8 %) and Actinomycetospora iriomotensis IR73-Li102(T) (98.2 %). However, the low level of DNA-DNA relatedness differentiated strain NEAU-st4(T) from its closest phylogenetic neighbours. The main chemotaxonomic properties of strain NEAU-st4(T), such as the diamino acid of the peptidoglycan, the whole-cell hydrolysates, the predominant menaquinones and the phospholipid profile, supported its classification within the genus Actinomycetospora. The distinctive morphology of this strain compared with that of other members in the genus Actinomycetospora is the formation of sporangia directly on the substrate hyphae. Phenotypic and genotypic differences also allowed the distinction of the strain from closely related species. Consequently, strain NEAU-st4(T) represents a new species of the genus Actinomycetospora, for which the name Actinomycetospora atypica sp. nov. is proposed. The type strain is NEAU-st4(T) (=CGMCC 4.7093(T) = DSM 45873(T)).