In Vitro Secondary Metabolite Production Through Fungal Elicitation: An Approach for Sustainability

Being sessile, plants produce an array of secondary metabolites in response to different biotic and abiotic stimuli to survive under adverse conditions. Many of these secondary metabolites are valued for their medicinal properties and are known for their usage to cure diseases since ancient time. Even after the discoveries of synthetic drugs, the interest for drugs derived from medicinal plants is gaining importance as they are safe and devoid of any side effects. A number of important medicinal plants are yet to be cultivated for commercial purposes and are collected from wild habitat, posing a threat to their existence. To protect the biodiversity and achieve the sustainability, development of alternative strategies for production of secondary metabolites is necessary. Plant cell, tissue and organ culture including hairy root cultures have shown great potential for production of secondary metabolites. However, sometimes, these cultures fail to synthesise adequate secondary metabolites compared to plants growing under natural condition. The production of secondary metabolites can be enhanced by using different elicitors, either biotic or abiotic, which act as stress agents and enhance the production of secondary metabolites in plant callus/cell suspension culture, root culture, shoot culture and hairy root culture. Fungal elicitor (including yeast extract) is one of the preferred elicitors used for this purpose. In this chapter, attempts have been made to provide a comprehensive account of the strategies used for increasing the production of secondary metabolites in different in vitro culture system using fungal elicitors. A brief account of elicitors, elicitations and general mechanism of elicitations has also been provided.