Streptomyces panaciradicis sp. nov., a β-glucosidase-producing bacterium isolated from ginseng rhizoplane.

A Gram-staining-positive actinobacterium, designated strain 1MR-8(T), was isolated from the rhizoplane of ginseng and its taxonomic status was determined using a polyphasic approach. The isolate formed long chains of spores that were straight, cylindrical and smooth-surfaced. Strain 1MR-8(T) grew at 10-37 °C (optimum 28 °C), whilst no growth was observed at 45 °C. The pH range for growth was 4.0-11.0 (optimum pH 6.0-8.0) and the NaCl range for growth was 0-7% (w/v) with optimum growth at 1% (w/v). Strain 1MR-8(T) had cell-wall peptidoglycans based on ll-diaminopimelic acid. Glucose, mannose and ribose were the whole-cell sugars. The predominant isoprenoid quinones were MK-9 (H4), MK-9 (H6) and MK-9 (H8) and the major fatty acids were anteiso-C(15:0), iso-C(15:0), anteiso-C(17:0) and iso-C(16:0). 16S rRNA gene sequencing studies showed that the novel strain was closely related to the type strains of Streptomyces caeruleatus GIMN4(T), Streptomyces curacoi NRRL B-2901(T), Streptomyces capoamus JCM 4734(T) and Streptomyces coeruleorubidus NBRC 12761(T) with similarities of 98.8%. However, DNA-DNA relatedness, as well as physiological and biochemical analyses, showed that strain 1MR-8(T) could be differentiated from its closest phylogenetic relatives. It is proposed that this strain should be classified as a representative of a novel species of the genus Streptomyces, with the suggested name Streptomyces panaciradicis sp. nov. The type strain is 1MR-8(T) ( = KACC 17632(T) = NBRC 109811(T)).