Melatonin: A potential abiotic stress regulator

Abstract

Abiotic stress adversely affects the metabolism and growth of plants, hampering their yield and productivity. Melatonin is a ubiquitous, multifunctional, regulatory, non-toxic potential bio stimulator possessing pleiotropic effects in the plant kingdom. It is a master regulator which plays a critical role under abiotic stress conditions. Studies indicate abiotic stress increases endogenous levels of melatonin in plants. On the other hand, exogenous melatonin has also been reported to mitigate abiotic stress in plants by modulating proteins and gene expressions. Melatonin-mediated reactive oxygen species scavenging and defense system activation are the primary mechanisms employed to make melatonin a master regulator in alleviating abiotic stress. This review summarizes recent research concerning phytomelatonin biosynthesis, its detection techniques, and its levels under abiotic stress conditions. We have focused on the regulatory effects of melatonin under drought, heat, cold, heavy metal, acid rain, toxic chemical, light, and herbicide stress. Additionally, the crosstalk of melatonin with other phytohormones has also been considered.