S-adenosylmethionine activates adpA transcription and promotes streptomycin biosynthesis in Streptomyces griseus

S-adenosylmethionine (SAM), the major methyl donor in diverse biological processes, was previously documented as a regulator for secondary metabolism in Streptomyces. The present study demonstrates that exogenous SAM, in a quantity as low as 10 mu M, enhanced streptomycin production and adpA transcription in both Streptomyces griseus wild-type strain and mutant HO1, which displays no ArpA repression on the adpA promoter. SAM also enhanced xylE expression driven by the promoter of adpA or strR in a heterologous host, S. lividans. This report substantiates that exogenous SAM promotes adpA transcription in S. griseus, which is involved in the SAM-mediated promotion of streptomycin, and that the mechanism underlying this event is shared in S. lividans.