Chemical elicitors and their impact on secondary metabolite production in Streptomyces

Streptomyces are typically known for their varieties of secondary metabolites, many of which hold significant pharmaceuticals. However, a major share of their biosynthetic capacity remains hidden because secondary metabolite-biosynthetic gene clusters are often silent under standard cultivation conditions. To switch on these cryptic genes, there is a need for such signaling molecules as physiological or environmental stress. These numerous signals, signal transduction proteins and transcription factors form an elaborate regulatory network. This triggers various responses, chief among them being the activation of secondary metabolism. In this review, we present evidence of how chemical elicitors can induce the expression of such cryptic genes. These cryptic genes can be activated with a better understanding of the genome sequencing, leading to novel drug discovery. Elicitors increase the synthesis of secondary metabolite compounds by signal transduction mechanisms and impact the growth and other cellular activities in Streptomyces such as carbohydrate and lipid metabolism protein production and gene activity. This underlined the importance of elicitor approaches and signaling-based strategies in developing and advancing secondary metabolite research and development.