Scientists at the University of California, Davis have engineered wheat plants that can enhance their own fertilizer production. The research team, led by Eduardo Blumwald, a distinguished professor in the Department of Plant Sciences, used CRISPR gene-editing technology to increase the amount of a natural chemical produced by wheat. This chemical, when released into the soil, supports bacteria that convert nitrogen from the air into a form usable by plants—a process known as nitrogen fixation.
The findings were published in Plant Biotechnology Journal. The development may offer significant benefits for food security in developing countries.
“In Africa, people don’t use fertilizers because they don’t have money, and farms are small, not larger than six to eight acres,” said Blumwald. “Imagine, you are planting crops that stimulate bacteria in the soil to create the fertilizer that the crops need, naturally. Wow! That’s a big difference!”
This innovation expands on previous work with rice and ongoing efforts to apply similar technology to other cereal crops. Wheat is currently the world’s second largest cereal crop by yield and accounts for about 18% of global nitrogen fertilizer use. According to United Nations Food and Agriculture Organization data, more than 800 million tons of fertilizer were produced worldwide in 2020.
However, only 30 to 50% of nitrogen from fertilizers is absorbed by plants; much of what remains can enter waterways or be released as nitrous oxide gas—contributing to environmental problems such as water pollution and climate change.
Traditional approaches tried to get cereal crops like wheat to develop root nodules or host nitrogen-fixing bacteria directly—techniques successful in legumes like beans and peas—but with limited results in cereals. Blumwald’s group took an alternative approach.
“For decades, scientists have been trying to develop cereal crops that produce active root nodules, or trying to colonize cereals with nitrogen-fixing bacteria, without much success. We used a different approach,” said Blumwald. “We said the location of the nitrogen-fixing bacteria is not important, so long as the fixed nitrogen can reach the plant, and the plant can use it.”
The team screened 2,800 chemicals naturally made by plants and identified twenty that help bacteria form biofilms—structures necessary for low-oxygen environments where nitrogenase enzymes can function efficiently. Using CRISPR editing, they increased levels of apigenin—a flavone—in wheat roots. Excess apigenin stimulated biofilm formation around soil bacteria during experiments and supported effective nitrogen fixation.
Hiromi Tajima was first author on a recent publication describing these developments.
Experiments showed that modified wheat yielded more grain under low-nitrogen conditions compared to control plants. In economic terms, U.S. farmers spent nearly $36 billion on fertilizers in 2023 across roughly 500 million acres planted with cereals.
“Imagine, if you could save 10% of the amount of fertilizer being used on that land,” said Blumwald. “I’m calculating conservatively: That should be a savings of more than a billion dollars every year.”
Other contributors include Hiromi Tajima, Akhilesh Yadav, Javier Hidalgo Castellanos, Dawei Yan, Benjamin P. Brookbank and Eiji Nambara.
A patent application has been filed for this technology by the University of California and is pending approval. Bayer Crop Science and UC Davis Will Lester Endowment supported this research.
