The University of Tehran supported this research by providing all the necessary eStrigolactone and salicylic acid simultaneously enhance the resilience of common bean against salt stress by strengthening the antioxidant defense system.

Salinity is a major abiotic stress that substantially reduces crop productivity worldwide. The common bean is especially vulnerable to salinity-induced damage. In this study, we assessed the physiological and molecular responses of salt-stressed common bean plants to foliar applications of salicylic acid (SA) and the synthetic strigolactone analogue GR24. Salinity stress increased electrolyte leakage and proline content while reducing relative water content, total protein, and photosynthetic pigments. Application of SA or GR24 individually improved tolerance, but their combined use provided greater protection, particularly by reducing electrolyte leakage. Both regulators enhanced antioxidant enzyme activities—including ascorbate peroxidase, superoxide dismutase, and catalase—by stimulating protein synthesis or limiting degradation. The SA+GR24 treatment partially restored photosynthetic pigment levels under salinity. Expression levels of SOD, CAT, APX, and GPX genes were upregulated in plants treated with both SA and GR24 under salt stress, underscoring the importance of these enzymes in redox homeostasis and stress tolerance. Collectively, SA and GR24 (1 mM SA + 10 μM GR24) acted synergistically to improve bio-physiological and metabolic functions under salinity, offering a promising approach to support plant recovery.