Researchers revealed that zinc is essential in the nitrogen fixation process of legumes. This study, together with the transcriptional regulator Fixation Under Nitrate (FUN), has the potential to transform legume-based agriculture by increasing crop efficiency and reducing dependency on synthetic fertilizers. Understanding how zinc and FUN influence nitrogen fixation may let researchers to increase nitrogen delivery, crop yields, and encourage more sustainable agricultural methods.
The new knowledge about zinc has the potential to revolutionize the way we cultivate crops by making plants more climate tolerant. This means that the plant can develop improved resistance to harsh weather, resulting in a more steady crop output, less reliance on artificial fertilizers, and the ability to cultivate legumes in previously inappropriate places.
FUN is regulated by a peculiar mechanism that monitor the cellular zinc levels directly and we show that FUN is inactivated by zinc into large filament structures and liberated into the active form when zinc levels are low
Professor Kasper Røjkjær Andersen
“Bacteria can work with legumes to fix nitrogen from the atmosphere in root nodules. However, the nodules are sensitive to environmental factors such as temperature, drought, flooding, soil salinity, and high nitrogen levels in the soil,” explains Assistant Professor and study lead author Jieshun Lin.
Researchers from Aarhus University in Denmark, working with the Polytechnic University of Madrid and the European Synchrotron Radiation Facility in France, revealed that legumes employ zinc as a secondary signal to integrate environmental parameters and modulate nitrogen fixation efficiency. In a study published in Nature, researchers revealed that FUN is a new sort of zinc sensor that decodes zinc signals in nodules and regulates nitrogen fixation.
“It’s truly amazing to discover zinc’s role as a secondary signal in plants.” It is an essential micronutrient that has never been used as a signal before. After screening over 150,000 plants, we discovered the zinc sensor FUN, which sheds insight on this interesting element of plant biology,” says Jieshun Lin.
In this study the researcher identifies that FUN is an important transcription factor that control nodule breakdown when soil nitrogen concentrations are high: “FUN is regulated by a peculiar mechanism that monitor the cellular zinc levels directly and we show that FUN is inactivated by zinc into large filament structures and liberated into the active form when zinc levels are low,” Professor Kasper Røjkjær Andersen explains.
From an agricultural perspective, continued nitrogen fixation could be a beneficial trait that increases nitrogen availability, both for the legume and for co-cultivated or future crops that rely on the nitrogen left in the soil after legumes are grown. This helps lay the foundations for future research that provides new ways for us to manage our farming systems and reduce the use of nitrogen fertilizer and reduce its impact on the environment.
The consequences of this study are considerable. Understanding how zinc and FUN regulate nitrogen fixation allows researchers to create strategies to improve this process in legume crops. This could result in enhanced nitrogen delivery, higher crop yields, and a reduction in the use of synthetic fertilizers, which have both environmental and economic consequences.
Researchers are now exploring how FUN generates and decodes zinc signals. They are excited to apply their new insights to legume crops like faba bean, soybean, and cowpea.
