Houston Daily

University of Houston engineers have found that melatonin, commonly known for its sleep-inducing effects in humans, has a different impact on plants by promoting their growth and helping them cope with stress.

Melatonin is a hormone produced naturally in the brain and also synthesized in laboratories. It is widely used as a sleep aid by about 27% of adults in the United States, where it helps regulate the body’s circadian rhythm.

“Melatonin has emerged as a pivotal molecule in agriculture due to its ability to promote plant growth and alleviate abiotic stresses,” said Abdul Latif Khan, assistant professor of engineering technology at the University of Houston, in an article published in iScience. Imad Aijaz, Khan’s graduate student, is the first author of the paper.

Aijaz explained that plants also have internal clocks which adjust various biological processes such as gene expression and metabolic regulation to match daily or seasonal cycles. “Because of this, circadian regulation enhances photosynthesis and growth rates and may influence crop flowering, seed yield, and responses to biotic and abiotic stresses,” he said.

Plants produce their own melatonin and receive additional amounts from microbes living near their roots. These microbes contribute further by making melatonin available for uptake by plants.

“Melatonin-producing microbes can enrich soils, enhancing melatonin availability, uptake, and transport within plants to improve stress tolerance and growth,” Khan said. His article reviews current knowledge about how melatonin is made in both plants and microbes, its roles in ecosystems and plant physiology, as well as future possibilities for using different microbes together to deliver melatonin to crops.

The research highlights strategies using melatonin as sustainable tools for managing crops. The team discusses how genetically engineered strains could be developed to help protect plants from disease, drought, or toxins.

Khan noted that most research so far has focused on major food or medicinal crops. “So far, most work has focused on species that are important for agriculture or health, but we know very little about how melatonin works in wild plants or those with cultural value. Studying these overlooked plants could help us understand how melatonin helps them survive harsh environments or adapt to changes in nature,” he said.