Melatonin Modulates Plant Tolerance to Heavy Metal Stress: Morphological Responses to Molecular Mechanisms

• Published in: International journal of molecular sciences Vol. 22; no. 21; p. 11445
• Main Authors: Hoque, Md Najmol, Tahjib-Ul-Arif, Md, Hannan, Afsana, Sultana, Naima, Akhter, Shirin, Hasanuzzaman, Md, Akter, Fahmida, Hossain, Md Sazzad, Sayed, Md Abu, Hasan, Md Toufiq, Skalicky, Milan, Li, Xiangnan, Brestič, Marián
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 23-10-2021; MDPI
• Subjects: Abiotic stress; Antioxidants; Antioxidants - metabolism; Antioxidants - pharmacology; Binding sites; Biosynthesis; Chloroplasts; Ecosystem; Enzymes; Fertilizers; Growth regulators; heavy metal; Heavy metals; Homeostasis; Lipid peroxidation; Melatonin; Melatonin - metabolism; Melatonin - pharmacology; Melatonin - physiology; Membranes; Metabolism; Metabolites; Metals, Heavy - metabolism; Metals, Heavy - toxicity; Molecular modelling; Morphology; Nutrients; Osmotic stress; Oxidation-Reduction; Oxidative stress; Oxidative Stress - drug effects; Oxidative Stress - physiology; Physiology; phytomelatonin; Plant growth; Plant Growth Regulators - metabolism; Plant tolerance; Plants - drug effects; Plants - metabolism; Proteins; Review; Soil - chemistry; Soil Pollutants - metabolism; Soybeans; Stress, Physiological - physiology; Sustainable agriculture; Toxicity; plant growth; heavy metal; phytomelatonin; oxidative stress; abiotic stress
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms222111445

Heavy metal toxicity is one of the most devastating abiotic stresses. Heavy metals cause serious damage to plant growth and productivity, which is a major problem for sustainable agriculture. It adversely affects plant molecular physiology and biochemistry by generating osmotic stress, ionic imbalance, oxidative stress, membrane disorganization, cellular toxicity, and metabolic homeostasis. To improve and stimulate plant tolerance to heavy metal stress, the application of biostimulants can be an effective approach without threatening the ecosystem. Melatonin (
-acetyl-5-methoxytryptamine), a biostimulator, plant growth regulator, and antioxidant, promotes plant tolerance to heavy metal stress by improving redox and nutrient homeostasis, osmotic balance, and primary and secondary metabolism. It is important to perceive the complete and detailed regulatory mechanisms of exogenous and endogenous melatonin-mediated heavy metal-toxicity mitigation in plants to identify potential research gaps that should be addressed in the future. This review provides a novel insight to understand the multifunctional role of melatonin in reducing heavy metal stress and the underlying molecular mechanisms.