The role of phytomelatonin in plant homeostasis, signaling, and crosstalk in abiotic stress mitigation.

In recent years, there has been an increase in the study of phytomelatonin. Having numerous functions in animals, melatonin produced by plants (phytomelatonin) is also a multi-regulatory molecule with great potential in plant physiology and in mitigating abiotic stresses, such as drought, salinity, chilling, heat, chemical contamination, and UV-radiation stress. This review highlights the primary functions of phytomelatonin as an anti-stress molecule against abiotic stress. We discuss the role of phytomelatonin as a master regulator, oxidative stress manager, reactive oxygen species and reactive nitrogen species regulator, and defense compounds inducer. Although there exist a handful of reviews on the crosstalk of phytomelatonin with other signaling molecules like auxin, cytokinin, gibberellin, abscisic acid, ethylene, nitric oxide, jasmonic acid, and salicylic acid, this review looks at studies that have reported a few aspects of phytomelatonin with newly discovered signaling molecules along with classical signaling molecules with relation to abiotic stress tolerance. The research and applications of phytomelatonin with hydrogen sulfide, strigolactones, brassinosteroids, and polyamines are still in their nascent stage but hold a promising scope for the future. Additionally, this review states the recent developments in the signaling of phytomelatonin with nitrogen metabolism and nitrosative stress in plants.