Unravelling the regulatory role of miRNAs in secondary metabolite production in medicinal crops

Abstract

Abstract Plant secondary metabolites (PSMs) such as flavonoids, terpenoids, alkaloids etc. have many biological, ecological and pharmaceutical significance Owing to their immense importance, elucidation of their regulatory mechanisms is pivotal. Micro-RNAs (miRNAs), the small, endogenous, noncoding RNA molecules of about 21 nucleotides, capable of regulating gene expression in eukaryotes, are off late gaining attention as potent engineer in regulating plant secondary metabolite synthesis. They have been used in metabolic engineering as they can target mRNAs for cleavage and translational repression thereby regulating key biological processes. However, knowledge on their role in plant secondary metabolite biosynthesis is still in its infancy. The present review comprehensively encompasses the regulatory role of miRNAs in the biosynthetic pathways of major plant secondary metabolites such as alkaloids, terpenoids and flavonoids with notes on their target genes and their biosynthetic products, kinds of regulatory miRNAs with their respective regulatory roles and methods of detection with a note on the future direction of relevant research.