New research suggests drought stress can affect not only crop growth, but also the nutritional quality of plants such as canola, rice and tomatoes.
New research from the University of Calgary has found that plants, including canola, rice and tomatoes, actively reduce their ability to take up iron when they experience drought.
The finding could have important implications for crop nutrition, especially as drought becomes more common in many agricultural regions.
The study, published in the journal Cell, also raises new questions about whether drought-stressed plants send out a kind of “cry for help” to attract beneficial soil microbes, such as bacteria and fungi, around their roots.
Roots Rewire Under Stress
“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 this shift allows a particular group of bacteria, called Streptomyces, to thrive around plant roots. However, that does not always translate into healthier crops. Some Streptomyces strains can benefit plants, while others may interfere with plant performance, according to a press release.
“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.”
Implications for Food Security
Fitzpatrick says the research is important for plant biology, but it also has broader implications for 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.”
Crop Yield and Nutritional Quality
Fitzpatrick, who completed his postdoctoral work at the University of North Carolina at Chapel Hill and finished the research at UCalgary, says the findings suggest drought and crop nutrition may be more closely connected than previously understood.
“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.
Testing the Mechanism Across Crops
Fitzpatrick says the research team first observed the reduction in iron uptake while studying how drought affects microbial communities around plant roots.
“We experimentally manipulated drought stress and iron availability to get at the mechanism,” he explains.
The team initially used Arabidopsis thaliana, a model plant often used in plant science, and later confirmed similar responses across several crop species.
“We’ve shown this for rice, we’ve shown this for tomato and, more recently, we’ve shown this for canola,” Fitzpatrick says.
A Path Toward More Resilient Crops
The findings could help guide future crop research, including the development of probiotic soil treatments or breeding strategies that allow crops to maintain iron uptake during drought.
Such approaches could support crops that are better able to withstand dry conditions while preserving nutritional quality.
