摘要
Cyclic dimeric GMP(c-di-GMP)has emerged as the nucleotide second messenger regulating both development and antibiotic production in high-GC,Gram-positive streptomycetes.Here,a diguanylate cyclase(DGC),CdgD,encoded by SCO5345 from the model strain Streptomyces coelicolor,was functionally identified and characterized to be involved in c-di-GMP synthesis through genetic and biochemical analysis.cdgD overexpression resulted in significantly reduced production of actinorhodin and undecylprodigiosin,as well as completely blocked sporulation or aerial mycelium formation on two different solid media.In the cdgD-overexpression strain,intracellular c-di-GMP levels were 13-27-fold higher than those in the wild-type strain.In vitro enzymatic assay demonstrated that CdgD acts as a DGC,which could efficiently catalyze the synthesis of c-di-GMP from two GTP molecules.Heterologous overproduction of cdgD in two industrial Streptomyces strains could similarly impair developmental transitions as well as antibiotic biosynthesis.Collectively,our results combined with previously reported data clearly demonstrated that c-di-GMP-mediated signalling pathway plays a central and universal role in the life cycle as well as secondary metabolism in streptomycetes.
Cyclic dimeric GMP(c-di-GMP) has emerged as the nucleotide second messenger regulating both development and antibiotic production in high-GC, Gram-positive streptomycetes. Here, a diguanylate cyclase(DGC), CdgD, encoded by SCO5345 from the model strain Streptomyces coelicolor, was functionally identified and characterized to be involved in c-di-GMP synthesis through genetic and biochemical analysis. cdgD overexpression resulted in significantly reduced production of actinorhodin and undecylprodigiosin, as well as completely blocked sporulation or aerial mycelium formation on two different solid media. In the cdgD-overexpression strain, intracellular c-di-GMP levels were 13-27-fold higher than those in the wild-type strain. In vitro enzymatic assay demonstrated that CdgD acts as a DGC, which could efficiently catalyze the synthesis of c-di-GMP from two GTP molecules. Heterologous overproduction of cdgD in two industrial Streptomyces strains could similarly impair developmental transitions as well as antibiotic biosynthesis. Collectively, our results combined with previously reported data clearly demonstrated that c-di-GMP-mediated signalling pathway plays a central and universal role in the life cycle as well as secondary metabolism in streptomycetes.
基金
supported by the National Natural Science Foundation of China (31630003, 31570072 and 31770088)
the Science and Technology Commission of Shanghai Municipality (18ZR1446700)
the National Science and Technology Major Project (2017ZX09101003-006-012)
