Actinomycetospora callitridis sp. nov., an endophytic actinobacterium isolated from the surface-sterilised root of an Australian native pine tree

An endophytic actinobacterium, strain CAP 335 ^T , was isolated from a root sample of a native pine tree growing on the Bedford Park campus of Flinders University, Adelaide, South Australia. The result of a polyphasic study showed that this strain was identified as a new member of the genus Actinomycetospora. This strain was observed to be a Gram stain-positive, aerobic actinobacterium with well-developed substrate mycelia and to form short chains of spores. Actinomycetospora chibensis TT04-21 ^T and Actinomycetospora straminea IY07-55 ^T were found to be close phylogenetic neighbours, each sharing 99.1% 16S rRNA gene similarity. Chemotaxonomic data including major fatty acids, cell wall components and major menaquinones confirmed the affiliation of strain CAP 335 ^T to the genus Actinomycetospora. The phylogenetic analysis, physiological and biochemical studies and DNA–DNA hybridization, allowed the genotypic and phenotypic differentiation of strain CAP 335 ^T and the closely related species with valid names. The name proposed for the new species is Actinomycetospora callitridis sp. nov. The type strain is CAP 335 ^T (= DSM 101857 ^T = NRRL B-65350 ^T ).