Phosphatidic acid priming-enhanced heat tolerance in tall fescue (Festuca arundinacea) involves lipidomic reprogramming of lipids for membrane stability and stress signaling

Phosphatidic acid (PA) is a key intermediate for lipid biosynthesis and an important second messenger mediating plant responses to environmental stresses. The objectives were to determine how PA priming could regulate plant tolerance to heat stress and to identify specific lipids and molecular species associated with PA-enhanced heat tolerance in tall fescue (Festuca arundinacea). Plants were exposed to heat stress (38/33 degrees C) for 14 days with or without foliar application of PA (25 mu M). PA-priming increased leaf dry weight, photochemical efficiency, and chlorophyll content and decreased leaf electrolyte leakage. Lipidomic analysis showed that the contents of PA, phosphatidylcholine (PC) and phosphatidylglycerol (PG), and digalactosyl diacylglycerol (DGDG), as well as acyl-chain length of phospholipids decreased under heat stress. The contents of PA-priming regulated major lipid molecular species, including PA (36:6), PG (32:1), PI (34:3), PI (36:5), PI (36:4), PI (36:3), PS (36:2), MGDG (34:4), MGDG (34:3), DGDG (34:3), were positively correlated to physiological traits of heat tolerance, which could serve as potential lipid biomarkers for improving heat tolerance in plants. The enhanced heat tolerance by PA-priming could be mainly attributed to lipid reprogramming with enriched lipids playing roles in stress signaling, and membrane stability and integrity.

Automated summary

PA priming can regulate plant tolerance to heat stress and specific lipid species are associated with enhanced heat tolerance. These findings are important for improving heat tolerance in plants and identifying lipid biomarkers.