Enhanced Secondary Metabolite Production in Hairy Root Cultures Through Biotic and Abiotic Elicitors

Abstract

Natural products from plants are of major pharmaceutical and therapeutic importance, several of which are often obtained from the underground parts of the concerned plants, necessitating the uprooting and killing of the whole plants. The biosynthetic capacity of “hairy roots” has appeared to closely mirror that of the roots of the parent plant from which they are derived and therefore has extensively been studied as an effective alternate system for in vitro secondary metabolite production. The growth rates and secondary metabolite yields of such transformed roots have also been improved by adopting several measures, such as: by alterations in nutrient composition, carbohydrate source and their levels, pH changes, supplementation with growth hormones, or elicitation with biotic or abiotic elicitors. Elicitors act by working as signals which are received by some elicitor-specific receptors present on the plant membranes, thus activating the defense responses which in turn lead to targeted secondary metabolite production. The present chapter discusses the effectiveness of different sources of elicitors (biotic or abiotic), their concentrations, and the time of application during hairy roots growth. The succeeding discussion in the chapter relates the present findings related to the genetically transformed “hairy root” cultures to the existing status of work on elicitation in medicinally important plant species for the maximum biomass and secondary metabolite production.