The Ameliorate Effects of Azelaic Acid on Salt Stress Tolerance in Glycine max L.

Azelaic acid (AzA) is recognized as an inducer of systemic acquired resistance under biotic stress; however, its role in plant cell wall regulation and reactive oxygen species (ROS) metabolism under abiotic stress remains unclear. This study investigated the physiological, biochemical, enzymatic and molecular responses of soybean plants treated with AzA under salinity stress.

In this experimental study conducted in 2024 at the Sinop University Plant Physiology Laboratory, 10-day-old soybean (Glycine max L.) plants were treated with AzA (12 and 24 ppm) and 250 mM NaCl. After 10 days, physiological parameters including growth, water status, chlorophyll content and electrolyte leakage were evaluated. Biochemical analyses included ROS content, hydroxyl radical scavenging capacity and proline accumulation. Antioxidant enzymes (SOD, CAT, POX, APX, GR, GST, DHAR and MDHAR), cell wall-related enzymes (PAL and PME) and expression levels of XTH3, EXPA2 and WAK4 genes were also analyzed.

AzA treatment alleviated salt-induced oxidative damage in soybean plants. It improved biomass, photosynthetic performance, membrane stability and ROS scavenging capacity under salinity stress. AzA also regulated antioxidant defense systems and enhanced PAL and PME activities associated with cell wall metabolism. Molecular analyses showed significant changes in XTH3, EXPA2 and WAK4 gene expressions in AzA-treated plants under salinity conditions. AzA plays an important role in improving salinity tolerance in soybean by regulating oxidative stress responses, antioxidant defense mechanisms and cell wall-related pathways. These findings provide new insights into the molecular and physiological mechanisms of AzA-mediated stress tolerance in plants.