Role of melatonin and serotonin in plant stress tolerance

Abstract

Melatonin and serotonin are human neuro-indoles and play pivotal roles in stress physiology and circadian rhythm modulation. Endogenous serotonin is a precursor molecule and plays a bottleneck role in the melatonin biosynthesis through the tryptophan biosynthesis pathway in plants and animals. Their role is well established in animal stress management and also has been sufficiently studied in plant physiology. Diverse sets of data are available in literature for the possible explanation of their roles in plants as a stress alleviator, delaying senescence, and flowering. Also, it is believed that their synthesis in plants is induced on both biotic and abiotic stresses. In addition, it is documented to have possible roles in roots and leaf growth, chlorophyll preservation, and fruit development. Also, it is evident that their exogenous application improves seed germination and postharvest fruit ripening to improve food quality. Exogenous application of serotonin promotes shoot induction, development, and multiplication and also is thought to be involved in pollen microspore development. Since their documentation in plants is so recent that it still needs a great deal of studies to uncover the significant roles of melatonin and serotonin in plants. This chapter comprehends the role of melatonin and serotonin in plant stress management. ? 2020 Elsevier Inc. All rights reserved.