Title:Melatonin Against Environmental Plant Stressors: A Review
Volume: 22
Issue: 5
Author(s): Marino B. Arnao*Josefa Hernández-Ruiz
Affiliation:
- Department of Plant Biology (Plant Physiology Unit), Faculty of Biology, University of Murcia, 30100-Murcia,Spain
Keywords:
abiotic stress, biostimulator, cold, drought, heat, heavy metals, plant growth, plant master regulator, plant tolerance,
salinity, stress signaling, UV radiation, waterlogging.
Abstract: Harsh or extreme environmental conditions largely determine the vegetative and reproductive
development of plants. In the case of cultivated plants, their growth and yield are clearly diminished
if they are exposed to severe conditions such as drought, waterlogging, extreme heat or
cold, UV radiation, or toxic substances in the soil such as salts, heavy metals and pesticides. Melatonin
has been studied for decades as a molecule capable of reducing the negative effects of abiotic
stressors by increasing tolerance to these adverse growth conditions. This work presents a review
of the most outstanding studies with various plant species in each of the above-mentioned stress situations,
including proteomic and post-translational studies. Melatonin mediates plant responses to
abiotic stress, generally inducing an antioxidative response, and also regulating a complex gene response
adapted to individual stressors. Plants are able to increase their endogenous melatonin levels
through the application of exogenous melatonin or through the inductive mechanism of endogenous
melatonin biosynthesis. In such ways, plants are able to cope with the stressful situation at
hand, accommodating their metabolism, morphology and physiology in order to increase overall
survival and induce greater tolerance to stress. The agronomic implications of the use of melatonin
are discussed.