Lipid metabolism improves salt tolerance of Salicornia europaea

Background and Aims Salicornia europaea L., a succulent euhalophyte plant, has been found to exhibit optimal reproductive capabilities under appropriate salinity concentrations. However, the underlying metabolic changes are not yet fully understood. Methods In this study, we conducted a comprehensive analysis combining transcriptomic and lipidomic techniques to investigate the molecular mechanisms of lipid metabolism in response to different NaCl concentrations (0 and 200 mM). Results Transcriptomic data demonstrated that salt treatment mainly affected processes including lipid biosynthesis, phosphatidylinositol signalling and glycerophospholipid metabolism. The expression levels of several key genes involved in salt tolerance, namely SeSOS1, SeNHX1, SeVHA-A, SeVP1 and SePSS, were found to be upregulated upon NaCl treatment. A total of 485 lipid compounds were identified, of which 27 changed in abundance during salt treatment, including the enrichment of phospholipids and sphingolipids. Moreover, the increase in the double-bond index was mainly attributable to phospholipids and sphingolipids. Comparing the acyl chain length showed that the acyl chain length coefficient of sphingosine-1-phosphate decreased significantly in the presence of 200 mM NaCl. Conclusions This study suggests that S. europaea adapts to saline environments by altering phospholipids and sphingolipids to improve salt tolerance. The salinity response of S. europaea can provide important insights into the action of lipids and their salt adaptation mechanisms.