Melatonin Applications in Plant Stress Tolerance

Melatonin, an indoleamine pervasive across living organisms, has emerged as a pivotal regulator of plant responses to both abiotic and biotic stresses. In plants, endogenous melatonin orchestrates a spectrum of protective mechanisms, including reactive oxygen species scavenging, modulation of phytohormone networks and preservation of photosynthetic integrity. Exogenous application of melatonin to crops has been shown to bolster tolerance to drought, salinity, extreme temperatures and heavy-metal toxicity by upregulating antioxidant enzymes, promoting osmolyte accumulation and enhancing membrane stability. Advances in molecular biology have unveiled key biosynthetic enzymes and regulatory modules that control plant melatonin levels, enabling strategies for metabolic engineering. Together, these insights underscore the global significance of melatonin in securing yield resilience under increasingly variable climates and in guiding the development of stress-hardy cultivars.

Research from Nature Portfolio

Recent studies have elucidated the genetic and cellular foundations of melatonin biosynthesis and its contribution to stress tolerance. A breakthrough investigation in tomato fruit revealed that red-light supplementation activates a photoreceptor-mediated pathway, culminating in the upregulation of enzymes that convert serotonin into melatonin. By precisely editing the promoter of a key methyltransferase gene, researchers engineered tomato lines with substantially enhanced melatonin content and improved resilience to post-harvest stress. In parallel, work on chloroplast function demonstrated that the organelle itself produces melatonin via a dedicated O-methyltransferase. Overexpression of this enzyme in model plants led to higher organellar melatonin levels, reduced chloroplastic reactive oxygen accumulation under salt stress and maintenance of photosynthetic capacity. These findings not only map critical biosynthetic steps but also offer routes for targeted enhancement of melatonin in crops.

Melatonin Applications in Plant Stress Tolerance publication trend

The graph below shows the total number of articles in melatonin applications in plant stress tolerance across all publications each year (not limited to Nature Index journals).

Technical terms

Melatonin: N-acetyl-5-methoxytryptamine, a multifunctional indoleamine that regulates plant stress responses and antioxidant defences.

Reactive Oxygen Species (ROS): Chemically reactive molecules derived from oxygen that can damage proteins, lipids and nucleic acids if not detoxified.

Phytochelatins: Small, cysteine-rich peptides that chelate and sequester heavy metals in plant cells, aiding in detoxification.

Redox Homeostasis: The balance between oxidation and reduction reactions in cells, crucial for maintaining metabolic and signalling processes.

Gene Editing: Precise modification of specific DNA sequences to alter gene expression or function, used to enhance melatonin biosynthesis in plants.

References

1. Understanding the mechanism of red light-induced melatonin biosynthesis facilitates the engineering of melatonin-enriched tomatoes. Nature Communications (2023).
2. Melatonin Synthesis and Function: Evolutionary History in Animals and Plants. Frontiers in Endocrinology (2019).
3. Melatonin mitigates cadmium phytotoxicity through modulation of phytochelatins biosynthesis, vacuolar sequestration, and antioxidant potential in Solanum lycopersicum L. Frontiers in Plant Science (2015).
4. Chloroplastic biosynthesis of melatonin and its involvement in protection of plants from salt stress. Scientific Reports (2017).