Study: While melatonin puts us to sleep, it wakes up plants

In an interesting turn of botanical events, University of Houston engineers report that while melatonin keeps us asleep, it wakes up plants, helping them grow.

Melatonin, a hormone produced in the brain and reproduced synthetically in labs, is America’s sleep drug of choice, taken by roughly 27 percent of U.S. adults. It helps control the body’s circadian rhythm or internal clock, signaling you that it’s time to go to bed.

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

“In plants, the internal clock can adjust the phase of various biological processes, such as gene expression, metabolic regulation and protein stability, to coincide with daily and/or seasonal cycles,” said Aijaz. “Because of this, circadian regulation enhances photosynthesis and growth rates and may influence crop flowering, seed yield, and responses to biotic and abiotic stresses.”

Like people, plants produce their own melatonin, plus they get help from tiny organisms, or microbes, that live near their roots and also produce the hormone.

“Melatonin-producing microbes can enrich soils, enhancing melatonin availability, uptake, and transport within plants to improve stress tolerance and growth,” said Khan, whose article reviews current understanding of melatonin biosynthesis in plants and microbes, its ecological and physiological roles, and the promise of getting different microbes to work together to transport melatonin.

The article highlights melatonin-based strategies as sustainable tools for crop management and outlines future directions for agricultural applications. Specifically, how scientists can create genetically engineered strains of melatonin that would protect plants from disease, drought and other toxins.

The researchers agree that plant melatonin research needs to move beyond just studying popular food and 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,” said Khan.