Strigolactone-mediated regulation of physiological, biochemical, and gene expression responses enhances salinity tolerance in strawberry (Fragaria × ananassa)

Salinity stress is a limiting factor that restricts growth, physiology, and fruit quality of strawberry (Fragaria × ananassa), particularly in irrigated and arid regions across the globe. The current investigation focused on unveiling the role of strigolactone (GR24, 5 µM) in the mitigation of NaCl-induced stress (100 mM) under greenhouse conditions. Salinity stress massively reduced plant performance, including fresh biomass (16.5 g), dry biomass (4.3 g), photosynthetic rate (7.9 μmol CO2 m−2 s−1), and fruit yield (6 fruits per plant), along with a decline in fruit quality (7.2 °Brix). In contrast, foliar application of strigolactone sig-nificantly enhanced the growth and productivity through restoring fresh biomass (26.5 g), photosynthesis (12.2 μmol CO2 m−2 s−1), and fruit yield (12 fruits plant−1). Improvement in strawberry fruit quality was also observed as a significant increase in TSS (9.1 °Brix) and acidity balance. Ionic homeostasis was also improved with the foliar application of strigolactone, as a reduction in Na+/K+ ratio (3.5 to 1.3), increasing K+ content (17 mg g−1 DW), and a reduction in Na+ accumulation (23 mg g−1 DW) was recorded, which resulted in improved membrane stability and reduced electrolyte leakage. Moreover, the antioxi-dant defense mechanism was strengthened, as displayed by increased SOD (72.4 U mg−1 protein) and POD (61.8 U mg−1 protein), while a reduction in MDA (19.3 nmol g−1 FW) and H2O2 (16.8 µmol g−1 FW) was also recorded. Expression of stress-responsive genes (FaMSD5, FaCSD7, FaCSD8, FaCSD10) confirmed the mitigation phenomenon. Current findings opened new avenues for researchers to validate at the field level and the interac-tion of strigolactone with other signaling pathways to optimize their application in sus-tainable agriculture, particularly strawberry production.