Streptomyces oryziradicis sp. nov., a novel actinomycete isolated from rhizosphere soil of rice (Oryza sativa L.).

A novel actinobacterium, designated strain NEAU-C40^T, was isolated from the rhizosphere soil of rice (Oryza sativa L.) collected from Northeast Agricultural University in Harbin, Heilongjiang province, north-east PR China, and was characterized using a polyphasic approach. On the basis of results of 16S rRNA gene sequence analysis, strain NEAU-C40^T belongs to the genus Streptomyces, and shares highest sequence similarities with Streptomyces polygonati CGMCC 4.7237^T (97.9%) and Streptomyces abietis DSM 42080^T (97.9%). Morphological and chemotaxonomic characteristics of the strain also supported its assignment to the genus Streptomyces. Cell walls contained ll-diaminopimelic acid and the whole-cell hydrolysates were glucose, rhamnose and ribose. The major menaquinones were identified as MK-9(H₈) and MK-9(H₆). The major fatty acids were iso-C_16:0, anteiso-C_15:0, C_16:0 and anteiso-C_17:0. The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol mannoside and an unidentified lipid. The genomic DNA G+C content of strain NEAU-C40^T was 71.8 mol%. Moreover, multilocus sequence analysis based on five other housekeeping genes (atpD, gyrB, rpoB, recA and trpB) and the low level of DNA-DNA relatedness allowed the isolate to be differentiated from its most closely related strains. On the basis of phenotypic, genotypic and phylogenetic data, strain NEAU-C40^T can be characterized to represent a novel species of the genus Streptomyces, for which the name Streptomyces oryziradicis sp. nov. is proposed. The type strain is NEAU-C40^T (=DSM 107943^T=CCTCC AA 2018038^T).