How Soybeans Defy Conventional Nitrogen Uptake

In general, plants obtain the nutrients they need for growth and development from the soil through their root systems. One of the most important nutrients is nitrogen, which is essential for key plant functions like photosynthesis, protein synthesis, and DNA/RNA production.

Most plants rely on the nitrogen naturally present in soil or added through fertilisers.

In nature, a unique group of plants, including soybeans, have evolved a special relationship with nitrogen-fixing bacteria in their roots. These bacteria are able to convert nitrogen gas from the air into a usable form that the plant can absorb through its roots. The bacteria live in specialised structures called root nodules that form on the soybean plant's root system.

Inside these root nodules, the nitrogen-fixing process requires a lot of energy. To support their bacterial partners, a research team led by Professor Boon Leong LIM of HKU School of Biological Sciences, in collaboration with The Chinese University of Hong Kong found that soybean plants have developed an ingenious adaptation - their root cells modify their mitochondria, the "powerhouses" of the cells, to boost energy production.

By increasing mitochondrial activity in the root nodules, the soybean plant is able to provide the considerable energy needed to fuel nitrogen fixation. This gives the soybean plant access to an abundant nitrogen supply, which is crucial for its growth and development.

It's a remarkable symbiotic relationship, where the plant provides carbon and energy sources for the bacteria, while the bacteria supply the plant with nitrogen nutrients. And it all happens underground, in those unassuming soybean root nodules.

Click here to learn more about the research.