Nitrogen Metabolism and Stress Responses in Leguminous and Non-Leguminous Plants

The management of nitrogen (N) metabolism underpins plant growth, productivity and resilience to environmental stress across leguminous and non-leguminous species. In legumes, root nodules host symbiotic rhizobia, enabling atmospheric N₂ fixation and ammonium assimilation, whereas non-legumes depend on soil-derived nitrate and ammonium uptake and subsequent reduction. Central enzymes—nitrate reductase, nitrite reductase, glutamine synthetase and glutamate synthase—coordinate the incorporation of inorganic N into amino acids, linking N metabolism to carbon pathways. Under abiotic stresses such as drought, salinity and nutrient imbalance, reactive oxygen species accumulate, triggering antioxidative responses and hormonal signalling cascades involving abscisic acid and jasmonic acid. Legumes modulate carbon allocation to nodules to maintain N₂ fixation under N deficiency, while non-legumes adjust root N uptake and engage osmoprotectants such as proline for osmotic adjustment. Cross-talk between N availability and stress tolerance mechanisms is evident in differential gene expression of transporters and enzymes, modulation of antioxidant capacity and remodelling of metabolite pools. Advancements in understanding the integration of N metabolism with stress physiology hold promise for breeding and biotechnological strategies to enhance crop performance, sustainable fertiliser use and resilience in a changing climate.

Research from Nature Portfolio

Excessive nitrogen application in wheat has been shown to impair antioxidant capacity during grain filling, leading to increased reactive oxygen species and lipid peroxidation that reduce yield. Metabolomic profiling revealed that overapplication of fertiliser disrupts nitrogen and secondary metabolism, highlighting the importance of optimising N inputs for balanced redox homeostasis and efficient grain development.

Nitrogen Metabolism and Stress Responses in Leguminous and Non-Leguminous Plants publication trend

The graph below shows the total number of articles in nitrogen metabolism and stress responses in leguminous and non-leguminous plants across all publications each year (not limited to Nature Index journals).

Technical terms

Nodule: Specialized root structure in legumes housing nitrogen-fixing bacteria.

Reactive oxygen species (ROS): Highly reactive molecules derived from oxygen that can cause oxidative damage.

Glutamine synthetase (GS): Enzyme catalysing the conversion of ammonium and glutamate into glutamine.

Osmoprotectant: Small molecule (e.g., proline) that helps maintain cell osmotic balance under stress.

Nitrate reductase: Enzyme reducing nitrate to nitrite in the first step of nitrate assimilation.

References

1. Front Cover: Nitrogen deficiency modulates carbon allocation to promote nodule nitrogen fixation capacity in soybean (EXP2 2/2024). Exploration (2024).
2. Excessive nitrogen application dampens antioxidant capacity and grain filling in wheat as revealed by metabolic and physiological analyses. Scientific Reports (2017).
3. PRpnp, a novel dual activity PNP family protein improves plant vigour and confers multiple stress tolerance in Citrus aurantifolia. Plant Biotechnology Journal (2023).
4. High Nitrogen Enhance Drought Tolerance in Cotton through Antioxidant Enzymatic Activities, Nitrogen Metabolism and Osmotic Adjustment. Plants (2020).