Streptomyces adonidis sp. nov., a novel actinomycete strain with antifungal activity isolated from the root of Adonis amurensis Regel

A novel endophytic actinomycete with antagonistic activity against Fusarium moniliforme, designated strain NEAU-BLH26^T, was isolated from the root of Adonis amurensis Regel collected at the horticultural experiment station of Northeast Agricultural University, Heilongjiang Province, northeast China. Strain NEAU-BLH26^T exhibited morphological and chemotaxonomic features of the genus Streptomyces. The diamino acid present in its cell wall was identified as LL-diaminopimelic acid, while galactose detected in whole-cell hydrolysates. The menaquinones were identified as MK-9(H₆), MK-9(H₈), and MK-9(H₄). The phospholipid profile comprised diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, two unidentified phospholipids and two unidentified aminolipids. The major fatty acids were determined to be iso-C_16:0 and C_16:0. The DNA G + C content, based on the genome sequence, was 70.5 mol%. Phylogenetic analyses of 16S rRNA gene and whole genome sequences analyses indicated that strain NEAU-BLH26^T was most closely related to Streptomyces geranii A301^T, with a 16S rRNA gene sequence similarity of 98.69%. However, the average nucleotide identity, average amino acid identity and digital DNA–DNA hybridization values confirmed that strain NEAU-BLH26^T represents a distinct species. This conclusion was further supported by phenotypic and chemotaxonomic differences between strain NEAU-BLH26^T and its closest relative. Additionally, the secondary metabolite biosynthetic gene clusters in strain NEAU-BLH26^T were predicted and analyzed. Based on phenotypic, chemotaxonomic and genotypic evidence, strain NEAU-BLH26^T is proposed as a novel species of the genus Streptomyces, for which the name Streptomyces adonidis sp. nov. is suggested. The type strain is NEAU-BLH26^T (= JCM 36414^T = MCCC 1K08678^T).