Salt Priming Enhances Salinity Tolerance in Creeping Bentgrass via Glycolipid Remodeling

Soil salinity is one of the most critical threats to plant development and agricultural productivity. Stress priming enhances plant resilience to subsequent severe stressors through prior exposure to mild stress. Understanding the mechanisms underlying priming-conferred salt tolerance and developing effective strategies are therefore crucial for sustainable agriculture. In the present study, creeping bentgrass (Agrostis stolonifera cv. ‘PennA4’) plants were pretreated with salt priming (150 mM NaCl) for 7 days, followed by exposure to severe salt stress (300 mM NaCl) for 14 days. Salt-primed plants exhibited superior growth performance under salt stress, with significant increases in leaf relative water content, chlorophyll content, and catalase activity, as well as decreases in electrolyte leakage and malondialdehyde content compared to non-primed plants. Lipidomic profiling analysis revealed that salt priming resulted in a 29.05% increase in the total lipid content during the priming stage. During subsequent salt stress, salt-primed plants maintained higher total glycolipid (21.70%) and monogalactosyl diacylglycerol (MGDG) (34.58%) levels than non-primed plants. Furthermore, salt priming increased the contents of specific glycolipid molecular species, including DGDG36:6, MGDG34:3, MGDG34:4, and MGDG36:6, resulting in increased unsaturation levels of digalactosyl diacylglycerol (DGDG) and MGDG. These findings demonstrate that salt priming enhances salinity tolerance by elevating the antioxidant capacity and promoting glycolipid remodeling, which are consistent with the preservation of chloroplast membrane integrity and thylakoid fluidity. This study thus establishes that enhanced antioxidant capacity and glycolipid reprogramming are important mechanisms for priming-induced stress adaptation, providing a theoretical foundation for improving plant resilience in saline soils.