Influence of exogenous elicitors on the production of secondary metabolite in plants: A review ("VSI: secondary metabolites")

During the whole lifespan from seedling to the mature stage, the plant produces a range of complex compounds usually known as Secondary Metabolites (SMs) for their cellular and physiological process. The quality and quantity of SMs in plants are influenced by various factors, including environmental conditions and abiotic/ biotic stress. These metabolites play a crucial role in helping the plant to adapt and survive in harsh environments. Moreover, SMs are the exclusive source of various bioactive compounds and are applied in a variety of commercially valuable products, including those in pharmacy, cosmetics, agriculture, and food/feed production and also offer huge opportunities for the development of new drugs against several diseases. As SMs have a broad range of applications, it is becoming increasingly important to explore and develop new strategies to increase their production in plants. The biosynthesis of these compounds occurs by various metabolic pathways. The regulation and plant content of SMs is significantly influenced by several elicitors. Enhanced production of SMs, a process known as elicitation, is an important area of research that has the potential to benefit the pharmaceutical and therapeutic industries. Elicitation can be achieved through a variety of abiotic and biotic elicitors. Furthermore, nowadays, Nanotechnology has emerged as a promising tool for enhancing the production of SMs in plants. Nanomaterials/Nanoparticles have great potential as abiotic elicitors for the synthesis of plant SMs. By using these methods to increase the yield of SMs in plants, researchers may be able to develop a new and more effective range of bioactive compounds. This review focused on plant SMs, abiotic elicitors (light, temperature, drought, salinity, ozone), biotic elicitors (bacteria, fungi, phytohormones, polysaccharides, and plant growthpromoting rhizobacteria), and also highlights nanoparticles as potential elicitors for enhancing the production of various SMs, as well as challenges and opportunities associated with the use of exogenous elicitors as a tool to enhance the production of SMs.