Streptomyces griseoruber Y1B, a Novel Streptomyces for 1-Hydroxyphenazine Production

Strain Y1B was isolated from a soil sample collected from Wuxi in Jiangsu Province, China. The strain was identified as Streptomyces griseoruber based on phenotypic characteristics and 16S rRNA gene sequence analysis. phzE and phzF gene fragments were amplified by PCR from S. griseoruber Y1B, and showed 70–80% similarity to those of phenazine-producing Pseudomonas and Streptomyces species, indicating that this strain contained phenazine biosynthetic genes and had the potential to produce phenazine compounds. A crude extract, obtained from S. griseoruber Y1B fermentation broth by organic solvent extraction and evaporation under reduced pressure, showed significant antifungal activity against Rhizoctonia solani, Pythiumultimum, and Fusarium oxysporum, and had a broad spectrum of antifungal activity. A phenazine compound, 1-hydroxyphenazine, and a shikimic acid-derived metabolite, benzoic acid, were separated and purified from the crude extract by preparative high performance liquid chromatography. The effects of addition of intermediate metabolites on 1-hydroxyphenazine production implied that the phenazine biosynthesis pathway in S. griseoruber Y1B might branch off from the shikimate pathway, using phenazine-1-carboxylic acid as the phenazine precursor. Furthermore, this is the first demonstration that S. griseoruber can produce phenazine compounds. Therefore, as a novel Streptomyces strain, S. griseoruber Y1B might have potential applications for biocontrol in agricultural production