A team of researchers from Aarhus University has made a significant breakthrough in understanding how certain plants can thrive without synthetic nitrogen fertilizers. Their study, published on November 6, 2025, in the journal Nature, reveals a genetic mechanism that could potentially reduce the reliance on artificial fertilizers in staple crops like wheat, maize, and rice.
Led by professors Kasper Røjkjær Andersen and Simona Radutoiu, the research identifies how specific genetic changes allow plants to form symbiotic relationships with nitrogen-fixing bacteria. These bacteria convert atmospheric nitrogen into a form that plants can utilize, enabling some plants, such as peas and clover, to grow without additional nitrogen input.
Understanding the genetic and molecular factors that facilitate this symbiosis is crucial. Currently, the production and use of synthetic fertilizers account for approximately 2% of global energy consumption and contribute significantly to carbon dioxide emissions. By enabling crops like barley and wheat to fix their own nitrogen, the researchers aim to mitigate both environmental impacts and agricultural costs.
The researchers focused on the role of plant receptors, which are proteins that detect signals from microorganisms in the soil. These receptors can differentiate between harmful and beneficial bacteria. The team discovered that two specific amino acids within these receptors play a critical role in determining whether a plant’s immune system is activated or whether it welcomes nitrogen-fixing bacteria for symbiosis.
Radutoiu highlighted the importance of this finding, stating, “This is a remarkable and important finding.” The researchers identified a section of the receptor protein they termed Symbiosis Determinant 1, which acts as a switch. By altering just two amino acids in this region, they could modify a receptor that usually triggers an immune response to instead promote cooperation with beneficial bacteria.
“This discovery shows that minor genetic changes can lead to significant shifts in plant behavior, transforming them from rejecting bacteria to cooperating with them,” Radutoiu explained.
In laboratory trials, the team successfully modified the plant Lotus japonicus to demonstrate this capability. They also confirmed that similar modifications could be applied to barley. Røjkjær Andersen remarked on the implications of their findings, saying, “It is quite remarkable that we are now able to take a receptor from barley, make small changes in it, and then nitrogen fixation works again.”
The researchers are optimistic about the future of this research. If the genetic modifications can be applied to widely cultivated cereal crops like wheat, corn, and rice, it could significantly change agricultural practices. Radutoiu cautioned that further research is needed, stating, “We have to find the other, essential keys first. Only very few crops can perform symbiosis today. If we can extend that to widely used crops, it can really make a big difference in how much nitrogen needs to be used.”
This research not only holds promise for sustainable agriculture but could also play a crucial role in addressing climate change by lowering greenhouse gas emissions associated with fertilizer production and use. The study serves as a stepping stone toward greener farming practices and food production methods.
For more information on this groundbreaking research, refer to the article by Simona Radutoiu titled, “Two residues reprogram immunity receptors for nitrogen-fixing symbiosis,” published in Nature.
