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Zinc’s Groundbreaking Impact on Nitrogen Fixation and Climate-Friendly Farming
Context: Researchers in France have discovered the crucial role of zinc in promoting the health and productivity of legume crops.
- The study published in the Nature Journal conducted by Denmark’s Aarhus University in collaboration with the Polytechnic University of Madrid shows how zinc significantly impacts nitrogen fixation.
Key Highlights
- Researchers discovered that legumes utilise zinc as a secondary signal to integrate environmental factors and regulate the efficiency of nitrogen fixation.
- They identified a genetic regulator called “Fixation Under Nitrate” (FUN) that acts as an “off switch” for nitrogen fixation in legumes.
- By studying 150,000 individual legume plants where specific genes were disabled to investigate how plants regulate the transition from nitrogen fixation to the uptake of soil nitrogen.
- The study identified an essential transcription factor that controls the breakdown of nodules when soil nitrogen levels are elevated.
What are legume plants?
- Legume is the fruit of plants in the pea family (Fabaceae).
- It includes beans, chickpeas, cowpeas, lentils, peas, peanuts, soybeans, and tamarind.
- Most legumes split open along two seams to release seeds. Some legumes, like peanuts and carobs, don’t naturally open.
- It provides food for humans and animals, edible oils, fibres, and even raw materials for plastics.
- Legume plants possess an exceptional ability to convert atmospheric nitrogen into usable nutrients through nitrogen fixation.
- However, this energy-intensive process is slowed when soil nitrate levels are already high due to natural processes or synthetic fertiliser applications.
Understanding Zinc’s Impact
- Zinc in plants plays a crucial role in nitrogen fixation, a process essential for converting atmospheric nitrogen into ammonia, a vital nutrient for plant growth.
- Legume crops form a symbiotic relationship with rhizobia, bacteria that fix atmospheric nitrogen within root nodules.
- These nodules are sensitive to various environmental factors including temperature, drought, flooding, soil salinity, and high levels of soil nitrogen.
The Zinc Sensor: Fixation Under Nitrate (FUN)
- FUN is a novel type of zinc sensor in legumes. It decodes zinc signals in nodules and regulates nitrogen fixation efficiency. When soil nitrogen concentrations are high, It controls nodule breakdown.
- It is activated or deactivated based on cellular zinc levels, forming large filament structures that release active FUN when zinc is inadequate
Implications for Agriculture
- By understanding zinc’s role in regulating nitrogen fixation, researchers aim to optimise crop productivity and resilience.
- Enhanced nitrogen fixation not only boosts crop yields but also reduces the dependency on synthetic fertilisers, thus mitigating environmental impact and production costs.
Future Directions:
- Researchers are delving deeper into the mechanisms through which zinc signals are generated and interpreted by FUN.
- This could lead to higher nitrogen delivery, increased crop yields, and a decreased reliance on synthetic fertilisers.
- They are currently studying the performance of common legume crops like soybean and cowpea under conditions where FUN activity has been disrupted or lost.
