How the "miniature switch" might change the fertilizer industry in India—and the greenhouse gas emissions that come with using fertilizer

The fight that the people of India are facing because of climate change will not only occur at the level of the policymaking chambers and the energy producers’ facilities, but also at the heart of their farmland, and now at the cellular level of the plants.

A recent study appeared in the scientific journal Nature and proposes that a tiny modification in a molecular structure might lower the use of urea fertilizer significantly in the Indian subcontinent, a huge source of carbon emissions. This study proposes that modifying two amino acids in a protein receptor of plants might enable cereals like wheat, rice, and corn to extract nitrogen from the atmosphere, a process currently enjoyed by a limited range of plants, the “legumes.”

“This is fundamentally a question of how plants respond to microbial cues,” they write. “The answer hangs on a small molecular switch that decides whether a plant mounts an immune response or establishes a symbiosis.”

Examples of such crops include lentils, garden peas, and soybeans that contain bacteria that could fix atmospheric nitrogen. These bacteria would render the fixed nitrogen available to the plants without requiring fertilizers. Cereals are plants that do not accept the bacteria and trigger the immune response to prevent interaction.

The trick, however, lies in the presence of receptor proteins on the plant’s root cells that work like gatekeepers. In legumes, there is a receptor protein named NFR1 that “actively suppresses immune alarms and symbiotic bacteria colonize the roots.” In cereals, “a receptor named CERK6 or RLK4 has the opposite function and views bacteria as pathogens.”

The Role of Plant Root Infection by Rhizobia

Rhizobia are bacteria that infect the plant roots. They form

By swapping two amino acids in this receptor’s “symbiosis determinant” region, they were able to reverse the signal. “The immune system is not switched off,” they write, “but rewired to discriminate between pathological and beneficial microorganisms, such as nitrogen-fixing bacteria.”

In barley plants, this mutation caused the evolution of root nodules like those found in legume crops. “The plant’s behaviour towards bacteria changed from hostile to symbiotic,” noted the researchers, adding that this was “a functional reawakening of an ancient biological pathway.”

But for those who study the climate, the stakes are high. “Urea production alone accounts for the consumption of about two percent of the world’s energy,” explains Zaitsev, “and the massive release of carbon dioxide.” “Excess fertilizer drifts into groundwater and nitrous oxide, a potent greenhouse gas that is 277 times stronger than carbon dioxide, is released into the atmosphere,” he continues

India is among the largest consumers of urea in the world and pays tens of thousands of crores every year to subsidise fertilizers. Statistics from both the government and the IPCC show a major area of use of urea to be the regions of Punjab, Haryana, and western Uttar Pradesh, where the major crops are wheat and rice.

“It would be a phenomenal benefit to the environment and also to the economy if our cereals are able to fix a small amount of nitrogen by themselves,” say agricultural scientists. Savings estimated by the Indian Council for Agricultural Research are a staggering ₹40,000 crore per annum, along with a reduction in emissions by a third for nitrous oxide," a council official adds.

Emissions aside, another aspect suggested to be alleviated is local environmental relief. "Regions experiencing urea-laden groundwater, like Punjab, would be highly relieved from chemical loading on soils and groundwater," the study states. Areas that are also climate change vulnerable, such as Bundelkhand and Bihar floodplains, will also be relieved from fertilizer usage that is dependent on fluctuations in monsoon patterns.a

However, according to scientists, the fact that the discovery worked in a lab is merely the beginning. As stated, “Translating this discovery to wheat, rice, and maize will require careful field trials, regulatory clarity, and public trust,” particularly in places such as India, where gene-edited crops are a politically delicate topic. But the message is, by and large, crystal clear. “Sometimes climate solutions are not about scaling up—but about switching on,” explains one scientist. Now, it is high time that a mere two amino acids could radically turn Indian agriculture into a low-carbon future and begin a Second Green Revolution, this time with the aid of climate-smart biotechnology, instead of fertilizers.