Scientists have discovered a new low-cost method of reducing the amount of nitrogen fertiliser required to grow cereal crops, which is beneficial to both farmers and the environment. Eduardo Blumwald, a distinguished professor of plant sciences, led the study, which discovered a new pathway for cereals to capture the nitrogen they require to grow.
The discovery may also benefit the environment by reducing nitrogen pollution, which can result in contaminated water resources, increased greenhouse gas emissions, and human health problems. The findings were published in Plant Biotechnology.
Nitrogen is essential for plant growth, and agricultural operations rely on chemical fertilizers to boost output. However, much of the applied material is lost due to leaching into soils and groundwater. Blumwald's research could lead to a more sustainable solution.
"Nitrogen fertilizers are prohibitively expensive," Blumwald explained. "Anything you can do to reduce that cost is critical." On the one hand, there is the issue of money, but there is also the issue of nitrogen's harmful effects on the environment."
Blumwald's research focuses on increasing soil bacteria's conversion of nitrogen gas in the air into ammonium, a process known as nitrogen fixation.
Peanuts and soybeans, for example, have root nodules that can use nitrogen-fixing bacteria to provide ammonium to the plants. Cereal plants, such as rice and wheat, lack this ability and must rely on inorganic nitrogen from fertilizers in the soil, such as ammonia and nitrate.
"If a plant can produce chemicals that cause soil bacteria to fix atmospheric nitrogen gas, we could genetically modify the plants to produce more of these chemicals," Blumwald explained. "These chemicals will stimulate bacterial nitrogen fixation in the soil, and the plants will use the ammonium formed, reducing the amount of fertilizer used."
Blumwald's team used chemical screening and genomics to identify compounds in rice plants that increased the bacteria's nitrogen-fixing activity.
The researchers then identified the chemical pathways and used gene editing technology to increase the production of compounds that stimulated the formation of biofilms. Bacteria in those biofilms improved nitrogen conversion. As a result, the bacteria's nitrogen-fixing activity increased, as did the amount of ammonium in the soil for the plants.
He described plants as "amazing chemical factories." "This could provide a long-term alternative agricultural practice that reduces the use of excessive nitrogen fertilizers."
Other plants could use the pathway as well. The University of California has filed a patent application for the technique, which is currently pending. UC Davis researchers Dawei Yan, Hiromi Tajima, Howard-Yana Shapiro, Reedmond Fong, and Javier Ottaviani contributed to the study, as did Bayer Crop Science's Lauren Cline. Ottaviani is also a Mars Edge research associate.
