Hormonal priming with indole-3-acetic acid modulates antioxidant defense, gene expression, and physiological responses under salinity in Limonium spp.

Introduction: cultivars, sky light and deep blue. Methods: One-month-old plants were exposed to 250 mM NaCl, with or without prior priming with IAA. To evaluate the effect of IAA on salt stress mitigation, morphological, physiological, biochemical and molecular investigations were carried out. Results: homeostasis, improving chlorophyll retention, and reinforcing the antioxidant defense system. Proline accumulation, total soluble protein content, and stomatal regulation were also positively influenced by IAA treatment. Also, the expression of salt-responsive genes (RD22, RD29A, SOS1, AtP5CS1, LbMYB48, and LbAPX3) was upregulated under salinity, with a stronger induction observed in IAA-primed plants. Discussion: These findings highlight the regulatory role of IAA in modulating physiological, biochemical, and molecular responses to salinity stress, thereby enhancing the salt tolerance of limonium. The study underscores the potential of IAA priming as a practical strategy for improving the performance of plants under salinity to support the restoration of saline ecosystems.