New path to combating global malnutrition found in soil

A new University of Delaware study has found that a naturally occurring soil microbe can boost protein-building amino acids in wheat. The finding by UD's Harsh Bais and others could pave the way for nutrient-rich staple crops — helping combat global malnutrition as fluctuations in weather reduce crop quality.

In the study, published in the journal Frontiers in Microbiology, Bais and a team of researchers from UD, Stroud Water Research Center and the Rodale Institute investigated how a bacteria naturally found in the soil that is beneficial to human health can enhance the levels of the amino acid and antioxidant ergothioneine in spring wheat. 

The researchers grew the spring wheat — one of the most widely consumed cereal crops — in a laboratory. After letting the seeds germinate and grow for seven days, they added a strain of bacteria called Streptomyces coelicolor M145 to the spring wheat roots. After combining the bacteria and the plant, they separated the plant’s leaves and roots. Then, they extracted the amino acid ergothioneine from the samples, working to determine how much protein was in the plant’s roots and shoots.

They found that 10 days after S. coelicolor had been added to the spring wheat roots, the bacteria was able to inhabit spring wheat’s roots and shoots, producing ergothioneine, bypassing the plant’s innate defense mechanisms, and fortifying the spring wheat.

Wheat roots were inoculated with the benign bacteria Streptomyces coelicolor. The image shows the presence of bacteria on the root hairs on day 5.

“It’s unusual," Bais said. “Unless there is a mutual advantage for either the plant or the microbe.”

The findings suggest that an alternative plant breeding approach could be utilized to associate plants with benign microbes to increase protein content in staple crops. All of our cereal crops are very low in protein. Think rice and breakfast cereals, common foods people eat, derived from these crops.

“This approach of harnessing a natural association of microbes with plants may facilitate fortifying our staple crops, enhancing global nutritional security,” Bais said.

Bais said he believes using microbes to transport nutrients depends on the microbes’ relationship with plants’ roots. He continues to work to catalyze the colonization of plant roots by beneficial microbes.

"Establishing a partnership with the appropriate types of microbes or microbial consortia for plants represents a method of engineering the rhizosphere — the region of the soil near plant roots — to foster a more favorable environment for either microbial associations that stimulate plant growth traits or enhance nutrient availability, which is the path forward,” Bais said.

Bais, a professor of plant biology who was named a UD Innovation Ambassador earlier this year, said plants’ “below-ground” traits, such as how nutrient-dense they are, have long been overlooked.

“As far as food security, we will have significant challenges by 2050 when the world’s population doubles,” Bais said. “We incentivize our farmers for crop yield; we don’t incentivize them for growing nutrient-dense crops. Growing nutrient-dense plants will enable the population to be fed better and avoid any potential nutrient deficiencies.”

The study was funded by the U.S. Department of Agriculture and the Foundation for Food and Agriculture Research.

Scientists have become more interested in soil bacteria as a means to solve issues with malnutrition and nutrient deficiencies. Alex Pipinos, the lead author and a UD Class of 2025 graduate with a master’s in microbiology, said environmental conditions are one factor diminishing protein content in plants.

“Essentially, crops are becoming less nutrient-dense,” Pipinos said. “The more nutrients in crops, the more healthy humans can be.”

Pipinos points to a strong link between soil microbes, plant health and human health. Ergothioneine, she said, has already been shown to lower the risk of cardiovascular disease. It’s also been shown to combat cognitive decline, with a strong link to healthy cognitive aging.

“By enhancing ergothioneine in plants, we can improve human health,” Pipinos said.

To reach Bais directly and arrange an interview, visit his profile and click on the contact button. Reporters can also contact UD's Media Relations Department.