Microbial interventions to induce secondary metabolite biosynthesis in medicinal and aromatic plants

Medicinal and aromatic plants (MAPs) are well known to produce a plethora of secondary metabolites that are important class of phytochemicals demonstrating enormous structural diversity. Considerable dilemma regarding their biological functions, immense array of pharmaceutical activities, and their uses as flavoring agents, insecticides, medicines, coloring dyes, and aromatic agent make secondary metabolites fascinating candidates for research. Microbial interventions offer numerous choices through which the biosynthetic pathway in MAPs can be improved in pioneering ways, to induce phytochemicals of concern, to diminish the number of toxic chemicals, or even to produce new compounds. Pathway modulation approach has been useful to enhance the content of the compounds of interest or novel metabolites. Microorganism-mediated enhanced expression of plant secondary metabolite biosynthesis regulatory genes in MAPs is useful to confirm their functions. The microorganisms normally colonize plant and qualitatively and quantitatively increase the biosynthesis of bioactive compounds in the host plant. Detailed investigation of microorganisms and the ways they affect the biosynthesis of secondary metabolites may offer surplus options to harness this resource. This chapter embodies the findings of modern investigations involving various microorganisms that could alter the expression of biosynthesis regulatory genes in MAPs and enhance the accumulation of plant bioactive compounds. The chapter also provides perspectives on future research in this field.