Bayer's Nitrogen-Fixing Grains: Gene-Edited Wheat That Makes Its Own Fertilizer

Bayer has taken a commercial licence for a technology that could change one of farming's oldest dependencies. The German crop-science giant has licensed work from the University of California, Davis, that edits grain plants so their roots recruit soil bacteria to fix nitrogen from the air, the same trick legumes perform naturally. Corn, wheat and rice, which together supply nearly half of the world's daily calories, cannot do this on their own, and so they depend on synthetic nitrogen fertilizer. That dependence is expensive, polluting and, as the last few years have shown, geopolitically fragile.

The science behind the licence is unusually elegant because it does not try to rebuild the legume. Legumes house nitrogen-fixing bacteria in root nodules, a structure cereals never evolved. Eduardo Blumwald's team at UC Davis took a different route: instead of moving the bacteria inside, they changed what the plant says to the bacteria already around it. Screening some 2,800 chemicals that plants produce naturally, the team found 20 that prompt soil bacteria to form protective biofilms. One of them, a flavone called apigenin that wheat already makes in small amounts, proved especially effective. Using CRISPR, the researchers edited wheat to produce more apigenin, which the plant releases through its roots. In their experiments, the extra apigenin coaxed bacteria into forming biofilms that shield nitrogenase, the oxygen-sensitive enzyme that does the actual fixing, and the edited wheat then took up the fixed nitrogen. Under low-nitrogen conditions, the edited plants also yielded more grain than unedited controls.

That is a laboratory result, and Bayer is not pretending otherwise. Its head of public affairs and sustainability, Matthias Berninger, called nitrogen fixation in cereals "one of the holy grails in our field" while adding, plainly, that the technology "could ultimately turn out not to work as intended". The next step is testing outside the greenhouse, and no product is expected before the next decade. Bayer is hedging in the meantime: in October it partnered with Stanford spinout Switch Bioworks, which engineers the root-dwelling microbes themselves rather than the plant. Two routes to the same field, one bet on the plant's chemistry, one on the microbe's.

The timing of the licence is not accidental. Synthetic fertilizer underpins roughly half of global food production, and its price has soared as supply disruptions linked to the war with Iran have rattled markets. Berninger noted that the European Union still gets nearly a quarter of its urea imports from Russia, and Bayer sees a slice of the roughly $85 billion urea market on offer, along with farmers left with more money to spend on seed and crop protection. In the United States alone, farmers spent nearly $36 billion on fertilizer in 2023, according to US Department of Agriculture estimates cited by UC Davis. A grain that makes even part of its own fertilizer would therefore matter twice over: as a cost saving and as a buffer against a supply chain that a small number of exporters can squeeze.

There is also a regulatory tailwind that did not exist a few years ago. Europe's new framework for gene-edited crops, approved by EU lawmakers this year, could smooth the path to market for precisely this kind of edit, which tweaks a plant's own chemistry rather than importing a foreign gene. That matters because the hardest part of this story was never the molecular biology in a glasshouse. It is whether a signal that works in controlled soil still works across soil types, climates and microbial communities that no laboratory can fully reproduce, and whether regulators and farmers accept it at scale.

What interests me most is the shift in thinking the licence represents. For a century, fertilizer strategy has been about feeding the plant from above: manufacture nitrogen at great energy cost, spread it on the field, and accept that much of it washes away into waterways and the atmosphere. The UC Davis approach feeds the plant from below, by recruiting an existing microbial workforce. It may fail in the field, as many elegant glasshouse results do. But if it survives contact with real soil, the payoff is not just cheaper wheat. It is a staple crop that is a little less hostage to energy prices, wars and a handful of exporters, and that is a kind of food security no subsidy can buy.