Activation of secondary metabolite–biosynthetic gene clusters by generating rsmG mutations in Streptomyces griseus

Abstract

Unlike other Streptomyces spp., the streptomycin producer Streptomyces griseus IFO13189 shows emergence of a small fraction of rsmG and rpsL mutants among spontaneous low- or high-level streptomycin-resistant mutants. rsmG, but not rpsL, mutants showed greater ability (two- to threefold) to produce streptomycin, accompanied by enhanced transcription of metK and strR, together with streptomycin biosynthetic genes, such as strB1, strD and strF, thus underlying the observed increase in streptomycin production in the rsmG mutants. Moreover, rsmG mutation was effective for activating the 'silent' or poorly expressed secondary metabolite-biosynthetic genes present in S. griseus.