Farewell to fertilizers? A step further

Industrial agriculture relies, among other things, on the use of nitrogen fertilizers to maintain high crop yields. Although nitrogen is the most abundant element in the atmosphere, plants are not able to take it and use it for growth. However, in nature some bacteria do have the ability to take nitrogen from the air and use it to grow thanks to an enzyme called nitrogenase. If we could get plants producing a functional nitrogenase enzyme, we could obtain crops that do not depend so much on nitrogen fertilizers. The overuse of these chemicals entails environmental problems such as the pollution episodes that have occurred recently in the Mar Menor (Murcia, Spain) or the more frequent events of algal blooms in California (US).

The NifB protein of nitrogen-fixing bacteria is responsible for producing a cofactor, in this case a metal compound, which is essential for the function of nitrogenase. Therefore, obtaining an active NifB protein in plants is critical to achieve crops that are independent of nitrogen fertilizers.

In the work developed by the Biochemistry of Nitrogen Fixation group of the CBGP, tobacco plants, a model organism in plant biotechnology, have been used to produce 30 NifB proteins from different microorganisms to select the candidates that presented the best behavior, i.e., stable and soluble in plant cells. Once this selection had been made, the chosen candidates were isolated from plants and the activity to produce this metal cofactor was studied in the lab. All chosen cadidates proved to be functional in producing this metal compound. These results bring us closer to obtain a functional nitrogenase in plants, reducing fertilizer inputs with the consequent economic and environmental benefits.

Original Paper:

Payá-Tormo, L., Coroian, D., Martín-Muñoz, S., Badalyan, A., Green, R.T., Veldhuizen, M., Jiang, X., López-Torrejón, G., Balk, J., Seefeldt, L.C., Burén, S., Rubio, L.M. 2022. A colorimetric method to measure in vitro nitrogenase functionality for engineering nitrogen fixation. 12, 10367. DOI: 10.1038/s41598-022-14453-x