TY - EJOU AU - He, Xiaomei AU - Wan, Xiaoting AU - Arif, Muhammad AU - Hu, Ziyang AU - Wang, Haiyu AU - Manzoor, Muhammad Aamir AU - Song, Cheng TI - Melatonin Biosynthesis, Growth Regulation, and Adaptability to Environmental Stress in Plants T2 - Phyton-International Journal of Experimental Botany PY - 2025 VL - 94 IS - 10 SN - 1851-5657 AB - Melatonin is a multifunctional molecule found in all organisms that has been shown to play a crucial role in plant growth, development, and stress response. Plant melatonin is typically synthesized in organelles termed chloroplasts, and the mechanisms of its synthesis and metabolic pathways have been extensively studied. Melatonin serves a significant regulatory function in plant growth and development, influencing the morphological and physiological characteristics of plants by modulating biological processes. While studies on plant melatonin receptors are in their early stages compared to studies in animal receptors, the binding mechanism with melatonin is now recognized as the key initiating step that triggers a series of downstream protective effects. This suggests that melatonin in plants may exert its effects through two main modes of target binding. The CAND2/PMTR1 protein binds to melatonin with a high degree of affinity. This binding activates downstream heterotrimeric G proteins, which trigger rapid intracellular signaling cascades. These cascades include activating the MAPK pathway and modulating ion channel activity. This action swiftly regulates stomatal closure in response to physiological processes such as drought stress. Additionally, melatonin has been demonstrated to regulate the plant stress response through two main mechanisms. First, it directly inhibits the accumulation of reactive oxygen species. Second, it indirectly influences the stress response pathways. This paper examines plant melatonin from three perspectives: the synthesis pathways of melatonin, its effects on plant growth, and its applications in plants under stress. Finally, the prospects for melatonin study and its applications in plants are discussed. KW - Melatonin; biosynthetic pathway; secondary metabolism; growth regulation; environmental stress DO - 10.32604/phyton.2025.070697