Melatonin-Induced Detoxification of Organic Pollutants and Alleviation of Phytotoxicity in Selected Horticultural Crops

Environmental pollution with organic pollutants has increased drastically in recent decades. Despite the importance of minimizing organic pollutant content such as pesticide residue in edible crops, our understanding of induced xenobiotic metabolism in plants is poor. Melatonin is a potent stress-relieving biomolecule, which exerts beneficial effects on xenobiotic metabolism in plants. Exogenous melatonin treatment not only improves photosynthesis, antioxidant defense, and plant growth but also reduces pollutant residue and xenobiotic uptake. The overexpression of melatonin biosynthetic genes enhances organic pollutant metabolism, while the suppression of endogenous melatonin biosynthesis increases organic pollutant residue in horticultural products. Studies have revealed that the glutathione-dependent detoxification pathway plays a critical role in the melatonin-induced enhanced detoxification of xenobiotics. Moreover, a role for RESPIRATORY BURST HOMOLOG (RBOH)-derived reactive oxygen species signaling has been revealed which potentially acts upstream of glutathione-dependent xenobiotic metabolism. Based on the literature, here, we reviewed the effects of organic pollutants on plants and how melatonin aids plants in enduring the effects of organic pollutant-induced stress. We also discussed the potential melatonin signaling mechanism in enhanced pesticide metabolism. Our assessment suggests that melatonin has positive impacts on plant tolerance to organic pollution, which can be used to improve the food safety of edible horticultural crops.