New Discovery Finds Zinc Can Make Crop Yields More Climate-Resilient

In a groundbreaking study, researchers have uncovered that zinc plays a vital role in the nitrogen fixation process of legumes. This discovery, along with insights into the transcriptional regulator known as Fixation Under Nitrate (FUN), has the potential to transform legume-based agriculture. By optimizing crop efficiency and reducing dependency on synthetic fertilizers, these findings could lead to more sustainable agricultural practices.  

Climate change, drought, rising temperatures, and other stressors pose significant challenges to agricultural sustainability. In a surprising breakthrough, researchers have uncovered that zinc plays a crucial role in how plants respond to abiotic stressors. This discovery not only enhances our understanding of the complex mechanisms underlying plant growth but also offers promising opportunities to enhance crop resilience, particularly in legume-based agriculture

Legumes, such as beans and peas, engage in a symbiotic relationship with rhizobia bacteria, which fix atmospheric nitrogen into a usable form within root nodules. However, these nodules are highly sensitive to various environmental conditions, including temperature fluctuations, drought, flooding, soil salinity, and high soil nitrogen levels.

A collaborative effort involving researchers from Aarhus University, the Polytechnic University of Madrid, and the European Synchrotron Radiation Facility in France has revealed that zinc acts as a secondary signal in legumes. This signal integrates environmental factors to regulate the efficiency of nitrogen fixation. Published in the journal Nature, the study found that FUN serves as a novel zinc sensor, decoding zinc signals in nodules to manage nitrogen fixation.

Assistant Professor Jieshun Lin, the study’s first author, highlighted the significance of the discovery, noting the remarkable revelation of zinc's role as a secondary signal in plants. Zinc, traditionally recognized as a vital micronutrient, had never been previously considered a signaling molecule. After screening over 150,000 plants, the study identified the zinc sensor FUN, shedding light on this fascinating aspect of plant biology. 

The research highlights FUN as a crucial transcription factor governing nodule breakdown in reaction to elevated soil nitrogen levels. Professor Kasper Røjkjær Andersen detailed that FUN is regulated through a distinctive mechanism that directly monitors cellular zinc concentrations. The study reveals that FUN forms extensive filament structures and deactivates under high zinc levels, reactivating when zinc levels decrease.

From an agricultural perspective, maintaining nitrogen fixation can be advantageous, increasing nitrogen availability for both the legume and subsequent crops. This foundational research paves the way for future studies that aim to improve farming systems and reduce the environmental impact of nitrogen fertilizers.

The implications of these findings are far-reaching. Understanding how zinc and FUN regulate nitrogen fixation could lead to strategies that enhance this process in legume crops. This advancement has the potential to increase nitrogen delivery, boost crop yields, and minimize the use of synthetic fertilizers, which have significant environmental and economic costs. Researchers are now delving deeper into the mechanisms by which zinc signals are generated and decoded by FUN.

They are eager to apply these discoveries to important legume crops such as faba beans, soybeans, and cowpeas, potentially revolutionizing legume-based agriculture for a more sustainable future.

(Source: Aarhus University)