Leguminous plants make agriculture sustainable

Among the various research projects conducted to make agriculture and, in particular, fertilisation more sustainable, there is the one conducted by the Institute of Biosciences and Bio-resources of the National Research Council of Naples (Cnr-Ibbr) with the aim of making agricultural soils more fertile by converting atmospheric nitrogen into nutrients that can be used by plants. Published in New Phytologist magazine, the project has made it possible to identify a new control mechanism for the correct functioning of the nitrogen-fixer nodule in leguminous plants.

In nature there are several nitrogen-fixing bacteria, such as Rhizobium strains, which form symbiotic associations with leguminous plants. These microorganisms can enter the root tissues, settling inside the plant cells, and grow to form a root nodule. By colonising the root nodules of the plant, the rhizobium enables the formation of this new organ able to convert atmospheric nitrogen into plant nutrients. This mechanism becomes crucial under stress conditions related to excess water, leading to a shortage of oxygen, which is insufficient to meet the energy requirements for atmospheric nitrogen fixing activity in leguminous crop nodules. In particular, the research illustrates the fundamental role played by a specific transporter that places nitrate inside the nodule.

“Leguminous crops represent a fundamental tool for a sustainable approach in agriculture, thanks to their ability to enrich the soils where they are grown with nitrogen,” explains Maurizio Chiurazzi, coordinator of the research project. “On the contrary, excessive nutrition of the soil through synthetic fertilisation pollutes the environment because only part of the nitrogen contained in fertilisers is assimilated by plants, while the rest remains in the soil and the microorganisms in the soil transform it into products that are a source of severe contamination of groundwater and the atmosphere.”