Functional roles of melatonin in plants, and perspectives in nutritional and agricultural science

• Published in: Journal of experimental botany Vol. 63; no. 2; pp. 577 - 597
• Main Authors: Tan, Dun-Xian, Hardeland, Rudiger, Manchester, Lucien C., Korkmaz, Ahmet, Ma, Shuran, Rosales-Corral, Sergio, Reiter, Russel J.
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.01.2012
• Subjects: Agriculture; Animals; Antioxidants; Antioxidants - metabolism; Arylamine N-Acetyltransferase - genetics; Beverages; Biological and medical sciences; Chlorophylls; Corn; Crops, Agricultural - chemistry; Crops, Agricultural - enzymology; Crops, Agricultural - genetics; Crops, Agricultural - immunology; Enzymes; Evolution, Molecular; Fundamental and applied biological sciences. Psychology; Health; Humans; Melatonin - genetics; Melatonin - metabolism; Melatonin receptors; Nutritional Sciences; Oxidative stress; Plant Immunity; Plant physiology and development; Plants; Plants, Genetically Modified; Receptors; REVIEW PAPER; Rice; Stress, Physiological; Vertebrates; Melatonin; Nutrition; Agronomy; Botany; plant; free radical biology; Agriculture; Biology; Antioxidant; Free radical
• ISSN: 0022-0957; 1460-2431
• DOI: 10.1093/jxb/err256

The presence of melatonin in plants is universal. Evidence has confirmed that a major portion of the melatonin is synthesized by plants themselves even though a homologue of the classic arylalkylamineN-acetyltransferase (AANAT) has not been identified as yet in plants. Thus, the serotoninN-acetylating enzyme in plants may differ greatly from the animal AANAT with regard to sequence and structure. This would imply multiple evolutionary origins of enzymes with these catalytic properties. A primary function of melatonin in plants is to serve as the first line of defence against internal and environmental oxidative stressors. The much higher melatonin levels in plants compared with those found in animals are thought to be a compensatory response by plants which lack means of mobility, unlike animals, as a means of coping with harsh environments. Importantly, remarkably high melatonin concentrations have been measured in popular beverages (coffee, tea, wine, and beer) and crops (corn, rice, wheat, barley, and oats). Billions of people worldwide consume these products daily. The beneficial effects of melatonin on human health derived from the consumption of these products must be considered. Evidence also indicates that melatonin has an ability to increase the production of crops. The mechanisms may involve the roles of melatonin in preservation of chlorophyll, promotion of photosynthesis, and stimulation of root development. Transgenic plants with enhanced melatonin content could probably lead to breakthroughs to increase crop production in agriculture and to improve the general health of humans.