Researchers at the John Innes Centre have made a groundbreaking discovery that could transform agricultural practices, making them more sustainable and reducing dependence on synthetic fertilizers. Their research has identified a biological mechanism that helps plant roots foster better relationships with beneficial soil microbes, which could significantly reduce the need for harmful chemical fertilizers.

The widespread use of nitrate and phosphate fertilizers in modern agriculture has led to environmental concerns due to their overuse, such as water pollution and soil degradation. In light of these challenges, researchers are increasingly turning to natural solutions, like the mutually beneficial relationships between plant roots and soil microbes, to improve nutrient uptake. This approach not only enhances plant health but could also help reduce reliance on synthetic fertilizers.

Dr. Myriam Charpentier and her team discovered a mutation in a gene in the legume Medicago truncatula, which reprograms the plant’s signaling system to strengthen its partnership with nitrogen-fixing bacteria, known as rhizobia, and arbuscular mycorrhiza fungi (AMF) that supply essential phosphorus. This relationship, called endosymbiosis, is a natural process where one organism lives within another to exchange nutrients. In return for sugars from the plant, these microbes help the plant access critical nutrients from the soil, reducing the plant’s need for artificial fertilizers.

While endosymbiosis has been known to improve nutrient uptake, its application in large-scale farming has been limited because it typically thrives in nutrient-poor soils. Intensive farming, however, is usually conducted on nutrient-rich soils, which creates a mismatch. This discovery, published in Nature, provides a solution: a mutation in a calcium signaling pathway that enhances these endosymbiotic partnerships in typical farming conditions.

The researchers’ findings are especially exciting because they showed that the same gene mutation that benefits legumes like Medicago truncatula also improves wheat’s ability to form beneficial relationships with nitrogen-fixing bacteria and AMF, even under field conditions. This breakthrough offers significant promise for broadening the use of natural, sustainable farming practices across a wide range of crops.

“Our findings hold great potential for advancing sustainable agriculture,” said Dr. Charpentier. “It is unexpected and exciting that the mutation we have identified enhances endosymbiosis in farming conditions because it offers the potential for sustainable crop production using endosymbionts alongside reduced inorganic fertilizer use.”

The discovery builds on earlier research by Charpentier’s team, which highlighted the crucial role of calcium signaling in root cell nuclei for establishing root endosymbiosis. The new study decodes this key signaling mechanism, showing how calcium oscillations regulate the production of flavonoids, which enhance the partnership between plants and microbes.

This work represents a crucial step toward replacing synthetic fertilizers with natural solutions. It addresses two critical challenges: improving nutrient uptake while reducing environmental damage caused by fertilizer overuse.

The broader implications of this research extend beyond the reduction of fertilizer use. Root endosymbiosis increases nutrient uptake and boosts plant resilience to environmental stresses such as drought and disease. As global agriculture faces mounting pressures due to climate change, increased demand for food, and the need for sustainable practices, this discovery provides a path forward. By enhancing the plant-microbe relationship, crops can become more efficient at absorbing nutrients, while also improving their resistance to disease and environmental stress.

Combining disease resistance and climate resilience with efficient nutrient assimilation through enhanced symbiotic relationships is a key strategy for meeting the growing global demand for high-yielding crops, without further damaging the environment.

This research is just the beginning. The findings provide a new avenue for developing crops that require fewer chemical inputs, which can benefit farmers economically while protecting the environment. Future research will focus on expanding these findings to a wider range of crops and improving the scalability of these practices for use in diverse agricultural settings.

As Dr. Charpentier concluded, “Our discovery underscores the importance of fundamental science in addressing societal challenges.” By developing crops that are more self-sufficient in nutrient uptake and more resilient to stress, this breakthrough opens up new possibilities for a future of agriculture that is both productive and sustainable.

By Impact Lab