A Systematic Review of Salinity Stress Responses in the Common Bean (Phaseolus vulgaris L.)
Common bean (Phaseolus vulgaris L.) represents one of the most critical grain legumes for direct human consumption, providing vital dietary protein, micronutrients, and calories worldwide. However, as an extreme glycophyte, Phaseolus vulgaris exhibits pronounced sensitivity to soil salinization, suffering severe yield penalties at electrical conductivity levels exceeding standard agricultural thresholds. Soil salinity inflicts primary osmotic shock and secondary cytotoxic ionic accumulation, which collectively compromise cell division, tissue elongation, photosynthetic efficiency, and membrane stability. Salinity also triggers excessive production of reactive oxygen species (ROS), causing lipid peroxidation, protein carbonylation, and premature organ senescence. Furthermore, the Rhizobium–legume symbiosis and biological nitrogen fixation apparatus within root nodules are exceptionally vulnerable to hyperosmotic and saline environments. This review synthesizes empirical findings across morphological, physiological, biochemical, transcriptomic, and genomic layers of salt stress responses in Phaseolus vulgaris. Furthermore, comprehensively evaluates salinity-induced perturbations in water relations, photosynthetic carbon assimilation, ion transport kinetics, antioxidant defenses, and nodulation biology, alongside modern genetic mapping and agronomic mitigation approaches.