title: Functions of melatonin in plants: a review.
abstract: The number of studies on melatonin in plants has increased significantly in recent years. This molecule, with a large set of functions in animals, has also shown great potential in plant physiology. This review outlines the main functions of melatonin in the physiology of higher plants. Its role as antistress agent against abiotic stressors, such as drought, salinity, low and high ambient temperatures, UV radiation and toxic chemicals, is analyzed. The latest data on their role in plant-pathogen interactions are also discussed. Both abiotic and biotic stresses produce a significant increase in endogenous melatonin levels, indicating its possible role as effector in these situations. The existence of endogenous circadian rhythms in melatonin levels has been demonstrated in some species, and the data, although limited, suggest a central role of this molecule in the day/night cycles in plants. Finally, another aspect that has led to a large volume of research is the involvement of melatonin in aspects of plant development regulation. Although its role as a plant hormone is still far of from being fully established, its involvement in processes such as growth, rhizogenesis, and photosynthesis seems evident. The multiple changes in gene expression caused by melatonin point to its role as a multiregulatory molecule capable of coordinating many aspects of plant development. This last aspect, together with its role as an alleviating-stressor agent, suggests that melatonin is an excellent prospect for crop improvement.
authors.affiliation: Department of Plant Biology (Plant Physiology), Faculty of Biology, University of Murcia, Murcia, Spain.
authors.forename: Marino B
authors.initials: MB
authors.lastname: Arnao
authors.affiliation: Department of Plant Biology (Plant Physiology), Faculty of Biology, University of Murcia, Murcia, Spain.
authors.forename: Josefa
authors.initials: J
authors.lastname: Hernández-Ruiz
mesh_terms: D018556:Crops, Agricultural / Q000378:metabolism*; D054884:Host-Pathogen Interactions; D008550:Melatonin / Q000378:metabolism*; D017440:Photoperiod; D010935:Plant Diseases; D018521:Plant Physiological Phenomena; D013312:Stress, Physiological; D014466:Ultraviolet Rays / Q000009:adverse effects
chemical_list: D008550:Melatonin
keywords: abiotic stress; antioxidant; biotic stress; circadian rhythm; melatonin; photosynthesis; phytomelatonin; plant growth; plant growth regulator; plant senescence; plant-pathogen interaction; reactive oxygen species (ROS); rhizogenesis; rooting; stress alleviation; stress-responsive factors