Spirillospora tritici sp. nov., a Novel Actinomycete Isolated from Rhizosphere Soil of Triticum aestivum L.

A Gram-positive, aerobic actinomycetes, designated strain SJ 21 T , was isolated from the rhizosphere soil of Triticum aestivum L. collected from Langfang, Hebei Province, Central China. Strain SJ 21 T with weak antifungal activity also contained genes (involved in antibiotics biosynthesis) of the nonribosomal peptide synthetases (NRPS), ketosynthase (KS) and methyl malonyl transferase domains (PKS-I) as well as KSα and KSβ domains (PKS-II). A polyphasic taxonomic study was carried out to establish the status of strain SJ 21 T . The strain formed spherical spore vesicles (7.0–8.9 µm) consisting of coiled and branched chains on aerial mycelia. 16S rRNA gene sequence similarity studies showed that strain SJ 21 T belongs to the genus Spirillospora and formed a distinct branch with its closest neighbour Spirillospora albida IFO 12248 T (98.7%). The morphological and chemotaxonomic properties of the strain are also consistent with those members of the genus Spirillospora . DNA–DNA hybridization experiments and phenotypic tests were carried out between strain SJ 21 T and S. albida , which further clarified their relatedness and demonstrated that SJ 21 T could be distinguished genomically from S. albida . Therefore, the strain is considered to represent a novel species of the genus Spirillospora , for which the name Spirillospora tritici sp. nov. is proposed. The type strain is SJ 21 T (=CGMCC 4.7420 T =JCM 32390 T ).