Streptomyces cyaneochromogenes sp. nov., a blue pigment-producing actinomycete from manganese-contaminated soil

A novel actinomycete isolate, designated strain MK-45(T), was isolated from soil sampled at a manganese-contaminated area in Xiangtan, China. The isolate formed extensively branched substrate mycelia and aerial mycelia that differentiated into tightly coiled or spiral spore chains with smooth-surfaced spores. The cell-wall hydrolysates contained LL-diaminopimelic acid and traces of meso-diaminopimelic acid. The major menaquinones consisted of MK-9(H-4), MK-9(H-6) and MK-9(H-8). The major polar lipids contained diphosphatidylgycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphotidylinositol and phosphotidylinositol mannosides. The predominant cellular fatty acids were iso-C-16:0, C(16:0 )and summed feature 3. Phylogenetic analysis based on the 16S rRNA gene sequences and concatenated partial sequences of the five protein-coding genes indicated that strain MK-45(T) was a member of the genus Streptomyces and most closely related to Streptomyces caeruleatus GIMN4.002(T) (99.5 % similarity), Streptomyces curacoi CGMCC 4.1680 (T) (99.5 %), Streptomyces shaanxiensis CCNWHQ 0031(T) (99.4 %) and Streptomyces cinnabarinus NRRL B12382(T) (98.9 %), respectively. However, the digital DNA-DNA hybridization values, the average nucleotide identity values and MLSA evolutionary distances between strain MK-45(T) and them showed that it belonged to a distinct species. Furthermore, the results of morphological, physiological and biochemical tests allowed further phenotypic differentiation of strain MK-45(T) from the four closely related type strains mentioned above and other species of the genus Streptomyces with which this strain has 98.0-99.2 % 16S rRNA gene sequence similarity. Therefore, it is concluded that strain MK-45(T) represents a novel species of the genus Streptomyces, for which the name Streptomycescyaneochromogenes sp. nov. is proposed, with MK-45(T) (=CICC 11045(T)=KCTC 49099(T)) as the type strain.