Nocardia callitridis sp. nov., an endophytic actinobacterium isolated from a surface-sterilized root of an Australian native pine tree.

A novel actinobacterium strain, CAP 290(T), was isolated from a surface-sterilized root of an Australian native pine tree, Callitris preissii. Comparative 16S rRNA gene sequence analysis showed that the strain belongs to the family Nocardiaceae. Strain CAP 290(T) was most closely related to Nocardia nova JCM 6044(T) (97.4 % 16S rRNA gene sequence similarity) and Nocardia terpenica IFM 0706(T) (96.7 %); similarity to other type strains of the genus Nocardia ranged from 95 to 97 %. Chemotaxonomic data [meso-diaminopimelic acid, major menaquinone MK-8(H(4omegacycl.)), major fatty acid C(16 : 0) and mycolate in the cell wall] confirmed the affiliation of strain CAP 290(T) to the genus Nocardia. The results of the phylogenetic analysis, together with the physiological and biochemical tests, allowed the differentiation of strain CAP 290(T) from strains of other Nocardia species. Therefore, strain CAP 290(T) represents a novel species, the first endophytic actinobacterium to be identified as belonging to the genus Nocardia, for which the name Nocardia callitridis sp. nov. is proposed. The type strain is strain CAP 290(T) (=DSM 45353(T) =ACM 5287(T)).