Investigations reveal zinc’s substantial effect on the nitrogen assimilation process in legumes, an insight with the potential to revolutionize cultivation of legume crops.
Global warming, water scarcity, heightened temperatures, and other adverse conditions pose challenges to the sustainability of agriculture. Now, researchers have made a serendipitous discovery: zinc is key in plants’ response to nonliving stress factors. This pivotal breakthrough not only enlightens us about plant development intricacies but also carries potential to overhaul the resilience of crops, predominately those that rely on legumes.
Elucidating Zinc’s Contribution to Nitrogen Fixation
Investigators have shed light on an indispensable function of zinc within the nitrogen assimilation process of legumes. This insight, coupled with a deeper understanding of the transcriptional controller known as Fixation Under Nitrate (FUN), holds the potential to reform legume cultivation by boosting crop efficacy and diminishing reliance on synthetic fertilizers. Research delves into how zinc and FUN govern nitrogen fixation, with goals to enhance nitrogen accessibility, bolster crop production, and advocate for farming techniques that are more aligned with environmental conservation.
Legume plants establish a mutualistic bond with rhizobia bacteria that convert atmospheric nitrogen into ammonium in root nodules. These nodules are, nonetheless, susceptible to a multitude of environmental threats such as variations in temperature, drought, excess water, soil salinity, and increased soil nitrogen content.
A Breakthrough in Plant Micronutrient Detection
Experts from Aarhus University, along with Polytechnic University of Madrid and European Synchrotron Radiation Facility in France, have pinpointed that legumes employ zinc as an auxiliary signal to merge environmental factors and modulate nitrogen fixation effectiveness. Detailed in Nature, the study established that FUN represents a novel class of zinc detector, interpreting zinc cues in nodules and modulating nitrogen fixation.
“The revelation of zinc’s role as an auxiliary signal within plants is indeed astounding. As an essential trace element, its signaling attribute was previously unrecognized. After reviewing upwards of 150,000 plants, we were able to pinpoint the zinc detector FUN, unveiling an engrossing dynamic in plant biology,” asserts Assistant Professor Jieshun Lin, the first author of the investigation.
Uncovering the Role and Mechanism of the FUN Protein
In their research, the team discerns that FUN is a crucial transcription factor that governs nodule disintegration when soil nitrogen levels rise. “FUN’s operation is steered by a unique mechanism that keeps tabs on the intra-cellular zinc concentrations, enabling FUN to switch from inactive large filament structures to its operative state when zinc abundance is low,” clarifies Professor Kasper Røjkjær Andersen.
From an agronomic viewpoint, maintaining nitrogen fixation could be a desirable quality that escalates nitrogen availability, benefitting not only the legume but also adjacent or subsequent crops that depend on the residual nitrogen in the soil post-harvest of legumes. This lays groundwork for further inquiry, paving the road for new methods to regulate our farming systems, curtail nitrogen fertilizer utilization, and mitigate its environmental footprint.
Advancing Efficiency and Sustainability in Agriculture
The significance of this exploration is considerable. By grasping how zinc and FUN steer nitrogen fixation, experts are concocting tactics to refine this process in legume vegetation. This approach could lead to augmented nitrogen supply, heightened harvests, and a reduction in the requirement for synthetic fertilizers, which frequently come with environmental and financial drawbacks.
Presently, researchers are deciphering the mechanisms behind the generation and interpretation of zinc indicators by FUN. They anticipate the application of these novel discoveries to leguminous crops like faba beans, soybeans, and cowpeas.
Citation: “Zinc mediates control of nitrogen fixation via transcription factor filamentation” by Jieshun Lin, Peter K. Bjørk, Marie V. Kolte, Emil Poulsen, Emil Dedic, Taner Drace, Stig U. Andersen, Marcin Nadzieja, Huijun Liu, Hiram Castillo-Michel, Viviana Escudero, Manuel González-Guerrero, Thomas Boesen, Jan Skov Pedersen, Jens Stougaard, Kasper R. Andersen and Dugald Reid, 26 June 2024, Nature.
DOI: 10.1038/s41586-024-07607-6
The support for this study came from the Enabling Nutrient Symbioses in Agriculture (ENSA) venture, which Bill & Melinda Gates Agricultural Innovations (INV- 57461), the Bill & Melinda Gates Foundation, and the Foreign, Commonwealth and Development Office (INV-55767) fund, along with a Carlsberg Foundation grant (CF21-0139) and funding from the European Research Council (ERC) as part of the European Union’s Horizon 2020 research and innovation programme (grant agreement No. 834221).
Filed patent inventors include Jieshun Lin, Peter K. Bjørk, Jens Stougaard, Kasper R. Andersen, and Dugald Reid for encapsulating these scholarly findings.
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