Transcriptomic and metabolomic analysis reveals that symbiotic nitrogen fixation enhances drought resistance in common bean.

This article investigates how the nitrogen source—symbiotic atmospheric nitrogen fixation (N₂ fixation) versus nitrate (NO₃⁻) fertilization—affects drought response in common bean (Phaseolus vulgaris L.), a key legume crop sensitive to water deficit. Using integrated transcriptomic and metabolomic analyses, the study found that although nitrate-fertilized plants exhibited more extensive gene expression changes under drought, N₂-fixing plants showed molecular and metabolic profiles more closely associated with drought tolerance, including higher accumulation of ureides, abscisic acid (ABA), proline, raffinose, amino acids, sphingolipids, and triacylglycerols. Physiologically, N₂-fixing plants maintained leaf relative water content better, exhibited stronger antioxidant enzyme activities, and recovered photosynthetic function and yield more effectively after drought compared to nitrate-fertilized plants. These findings suggest that symbiotic nitrogen fixation enhances drought resilience in common bean through coordinated molecular, metabolic, and physiological mechanisms, supporting its role in sustainable agriculture under water-limited conditions.