Streptomyces adelaidensis sp. nov., an actinobacterium isolated from the root of Callitris preissii with potential for plant growth-promoting properties.

An endophytic actinobacterium, strain CAP261T was isolated from the surface sterilized root of Callitris preissii (Australian native pine tree). As a result of a polyphasic taxonomy study, this strain was identified as a member of the genus Streptomyces. This strain was an aerobic actinobacterium with well-developed substrate mycelia with loop spore chains and the spore surfaces are verrucose. The closest phylogenetic members which shared the highest 16S rRNA gene sequences similarity was Streptomyces bottropensis ATCC 25435 T at 98.1%. Chemotaxonomic data including cell wall components, major menaquinones, and major fatty acids confirmed the affiliation of strain CAP261T to the genus Streptomyces. The results of the phylogenetic analysis, including physiological and biochemical studies in combination with genome comparison study, allowed the genotypic and phenotypic differentiation of strain CAP261T and the closest species with validly published names. ANIb, ANIm and dDDH values of strain CAP261T and S. bottropensis ATCC 25435 T were 86.7%, 89.2% and 33.9%, respectively. The name proposed for the new species is Streptomyces adelaidensis sp. nov. The type strain is CAP261T (= DSM 42026 T = NRRL B-24814 T).