New research by scientists at the University of Calgary has found that plants, ranging from canola to rice to tomatoes, actively shut down their own ability to take up iron when they experience drought.
It’s a finding that could have implications for the nutritional value of agricultural crops.
The study, published in the journal Cell , questions whether plants send out a "cry for help" when they are stressed by drought to recruit beneficial soil microbes (e.g., bacteria and fungi) in their roots.
“We found that this shift is the result of specific changes to plant roots,” says Dr. Connor Fitzpatrick, PhD, lead author on the study and now an assistant professor in the Department of Biological Sciences with UCalgary’s Faculty of Science. “It happens because plants, under drought stress, dial down both their immune systems and their iron uptake machinery.”
Fitzpatrick says that allows a particular group of bacteria, called Streptomyces, to thrive — but it doesn’t automatically mean healthier plants. Some Streptomyces strains help, he explains, while others interfere.
“Together, this leads to a new way of thinking about plant-microbe interactions during drought,” he says. “Drought doesn’t just stress plants. It fundamentally rewires how they manage nutrients and interact with the microbial world around them.”
Fitzpatrick says the research is important for plant biology, but also provides insight into global food security and human nutrition.
“Iron deficiency is already one of the most widespread nutritional disorders in the world, affecting billions of people,” he says. “Much of the iron in human diets comes from plants such as cereals and legumes.
“At the same time, drought is increasing in frequency and severity across many agricultural regions due to climate change.”
Fitzpatrick, who did his postdoctoral work at the University of North Carolina at Chapel Hill and finished the research at UCalgary, says the research suggests the challenges could be more connected than previously appreciated.
“It means drought may not only reduce crop yield, but also reduce the nutritional quality of crops by limiting iron in edible tissues," he says.
Fitzpatrick says the research team found the reduction in iron uptake as they were trying to understand microbial enrichment in plant roots.
“We experimentally manipulated drought stress and iron availability to get at the mechanism,” he explains.
The team initially used a model organism, Arabidopsis thaliana, known as the fruit fly of the plant world, and later demonstrated it across a wide variety of plants.
“We’ve shown this for rice, we’ve shown this for tomato and, more recently, we’ve shown this for canola,” Fitzpatrick says.
The research opens the door to creating probiotic soil treatments or ways of breeding crops that sustain iron uptake during a drought, he adds.
Cell
Experimental study
Streptomyces enrichment in roots during drought is uncoupled from plant benefit and is driven by host suppression of iron uptake and immunity
8-May-2026
The authors declare no competing interests.