Curiosity-driven research at the University of Wisconsin unearths nitrogen-fixing corn

When I was in graduate school in the early 1980s, I remember hearing Winston Brill, a professor of bacteriology at the University of Wisconsin-Madison, on the radio. Brill was predicting that in the coming years we would develop corn capable of incorporating nitrogen from the air into its tissues, reducing this important crop’s hunger for soil-applied fertilizers. This trait is called symbiotic nitrogen fixation, and is well-known in legumes, like soybeans, due to their ability to partner with microbes in the soil that can convert the inert nitrogen gas into forms that plants can use. But cereals like corn, it was thought, lack this microbial collaboration.

I was researching this very process, so with the hubris of youth, I scoffed, betting that science wouldn’t surmount the challenge of achieving nitrogen fixation in corn in my lifetime. Fortunately, I was wrong. In recent days, we learned that UW-Madison scientists in the College of Agricultural and Life Sciences, along with their colleagues at the University of California, Davis and Mars Inc., discovered indigenous varieties of corn capable of cooperating with bacteria to fix up to 80% of the nitrogen that the crop needs.

This stunning discovery has upended how we think about nitrogen fixation, and this important new trait may one day find its way into Wisconsin corn, a $1.6 billion business. Fertilizer makes up roughly 22% of the cost of producing corn, apart from the cost of land. Skimping on fertilizer can compromise crop yield, but excess fertilizer can run off the soil, impacting water used for swimming, fishing and drinking. Therefore, reducing corn’s need for fertilizer would be a boon for farmers and water quality alike.  

Professor of Agronomy and Bacteriology Jean-Michel Ané and his collaborators found the corn in Oaxaca, in southern Mexico. There, farmers grow corn with little or no fertilizers, yet it grows to a skyscraping 16 feet. Looking closer, they saw sets of thick above-ground roots producing globs of sugary gel. Their curiosity led them to wonder if this unusual gel helped the corn grow despite the nutrient-depleted soil.

In addition to experiments in Mexico, Ané brought the corn back to Wisconsin. With assistance from corn experts, professors Natalia de Leon and Shawn Kaeppler, Ané grew the corn at the Hancock and West Madison Agricultural Research Stations and on campus in the Biotron, one of the few controlled-growth facilities tall enough to accommodate this special plant. 

Ané’s research team brought out every possible test to verify what seemed so improbable when I was younger — that the gel clinging to the roots harbored a mini-ecosystem, including unique bacteria capable of fixing nitrogen, and that the airborne roots absorbed this nitrogen into the plant’s tissues. Between Ané’s expertise in bacterial communities and UW-Madison’s agricultural know-how, this discovery depended upon Wisconsin’s interdisciplinary collaborations and specialized research facilities.

While years of additional research will be required, scientists hope to breed this amazing nitrogen-fixation trait into modern cultivars of corn. If they and their colleagues are successful, Wisconsin farmers may one day have the option to grow corn that fixes nitrogen, much like their soybeans already do. In the meantime, UW-Madison scientists will continue following their curiosity, knowing that their discoveries will one day improve the lives of Wisconsinites.

What became of Brill after I doubted his prediction? He established the Cetus campus in Middleton, a biotechnology powerhouse that was eventually acquired by Monsanto and donated to UW-Madison two years ago. Now led by Kaeppler, the Wisconsin Crop Innovation Center, managed by the College of Agricultural and Life Sciences, is working to develop improved varieties and better techniques for growing crops, while providing space for the next generation of curiosity-driven research into plant growth.

It is the foresight of visionaries such as Brill and the curiosity of researchers like Ané that are the backbone of the Wisconsin Idea, the university’s commitment that our work is not done until it reaches every home, or dinner plate, in the state.

Kathryn VandenBosch is the dean of the College of Agricultural and Life Sciences at the University of Wisconsin-Madison.