Phytomelatonin: A new class master plant hormone with multiple roles

Phytomelatonin, a plant hormone derived from tryptophan, has emerged as a fascinating molecule with diverse physiological functions in plants. In recent years, extensive research has shed light on the multiple roles of phytomelatonin in various aspects of plant growth, development, and stress responses. The accumulating evidence emphasizes the importance of phytomelatonin as a key regulator in plant physiology and highlights its potential applications in crop improvement and stress tolerance. This review article aims to provide a comprehensive overview of the current knowledge regarding phytomelatonin and its multifaceted roles in plants. We discuss the biosynthesis of phytomelatonin and its involvement in regulating plant growth processes such as circadian rhythm, root development, and flowering. Furthermore, we highlight the crucial roles of phytomelatonin in modulating plant responses to various abiotic and biotic stress factors. Even though the effectiveness of melatonin through exogenous application has been well established in plant’ tolerance to stressful conditions, studies have just concentrated on the significance of high endogenous melatonin levels in enhancing the plant's ability to withstand stressors. Therefore, this review will also underline the importance of endogenous melatonin and shed light on how plants with high levels of melatonin respond to various stress conditions. Overall, this review will provide a foundation for further research on phytomelatonin and its potential implications in plant science and agriculture.