Open Access

REVIEW

Melatonin Biosynthesis, Growth Regulation, and Adaptability to Environmental Stress in Plants

Xiaomei He¹, Xiaoting Wan¹, Muhammad Arif ², Ziyang Hu¹, Haiyu Wang¹, Muhammad Aamir Manzoor^3,*, Cheng Song^1,*

1 College of Biological and Pharmaceutical Engineering, West Anhui University, Lu’an, 237012, China
2 Department of Plant Protection, Faculty of Agriculture, Sakarya University of Applied Sciences, Arifiye, 54580, Sakarya, Turkey
3 National Key Laboratory for Tropical Crop Breeding, School of Breeding and Multiplication (Sanya Institute of Breeding and Multiplication), Hainan University, Sanya, 572025, China

* Corresponding Authors: Muhammad Aamir Manzoor. Email: ; Cheng Song. Email:

(This article belongs to the Special Issue: Abiotic Stress Tolerance in Crop Plants: Physio-biochemical and Molecular Mechanisms)

Phyton-International Journal of Experimental Botany 2025, 94(10), 2985-3002. https://doi.org/10.32604/phyton.2025.070697

Received 22 July 2025; Accepted 16 September 2025; Issue published 29 October 2025

Abstract

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.

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