Synergistic effects of salicylic acid and GR24 in enhancing salinity tolerance in common bean (Phaseolus vulgaris L.): an integrated physiological, biochemical, and molecular approach

Abstract Soil salinity severely limits crop productivity worldwide, particularly in legumes such as common bean. This study investigated the independent and combined effects of salicylic acid (SA; 1 mM) and the strigolactone analogue GR24 (10 µM) on two bean cultivars exposed to 200 mM NaCl. Salt stress markedly decreased relative water content (RWC), photosynthetic pigments, and total protein, while increasing electrolyte leakage (EL), malondialdehyde (MDA), proline, and hydrogen peroxide (H₂O₂). Application of SA and GR24 significantly alleviated these effects by improving RWC, restoring pigments, reducing EL, MDA, and H₂O₂, and modulating proline levels. All measurements were based on three biological × three technical replicates. SA + GR24 also enhanced antioxidant enzyme activities (CAT, APX, SOD, GPX) and up-regulated the corresponding genes. These results provide an integrated hormonal approach for improving crop resilience under saline environments.