The Biosynthesis of Melatonin in Plants and the Mechanism of Its Influence on the Quality of Harvested Fruits

Melatonin is a small-molecule indoleamine compound that is essential to life. It is widely present in plants and plays an extremely important role in plant growth and fruit quality. This article summarizes the role of melatonin synthesis in plants, its distribution in some fruits, and its impact on post-harvest fruit quality. The mechanisms by which melatonin regulates post-harvest fruit quality are discussed in depth from the perspectives of respiratory metabolism, ethylene metabolism, sugar metabolism, reactive oxygen species (ROS), and antioxidant systems. Finally, we analyze the existing problems in the current research field of melatonin in post-harvest fruit preservation and look toward the application prospects of melatonin synthesis, metabolism, and the mechanisms for regulating fruit quality. This article provides a reference for further exploring the role of melatonin and increasing the endogenous content of melatonin in fruits, as well as post-harvest preservation techniques, with the aim of promoting the application of melatonin in post-harvest preservation.