Triacylglycerols at the crossroads of lipid remodeling and stress tolerance in plants.

Triacylglycerols (TAGs), once considered passive storage reserves confined to seeds, are now recognized as dynamic components of plant lipid metabolism with pivotal roles in stress adaptation. Far from being inert carbon depots, TAGs function as metabolic buffers that integrate energy storage, membrane lipid remodeling, and cellular protection under fluctuating environmental conditions. Abiotic stresses such as temperature extremes, drought, salinity, and nutrient limitation disrupt membrane integrity and lipid homeostasis, leading to the release of free fatty acids and the accumulation of reactive oxygen species (ROS). TAG biosynthesis under these conditions acts as a protective sink, sequestering toxic lipid intermediates, preserving membrane stability, and maintaining redox balance. The dynamic turnover between membrane lipids and TAGs allows plants to rapidly reorganize their lipid composition, stabilizing membranes during cold or heat stress, buffering osmotic imbalance during drought and salinity, and mitigating photodamage under nutrient deprivation. Emerging evidence highlights that TAG accumulation is not merely a byproduct of stress but a strategically regulated process linked to hormonal and redox signaling pathways. This reprogramming of lipid metabolism supports energy redistribution, detoxification of reactive lipid species, and recovery following stress exposure. This review summarizes recent advances in understanding the biosynthetic, regulatory, and physiological roles of TAGs during abiotic stress. It discusses how TAG metabolism operates at the intersection of lipid remodeling, cellular homeostasis, and stress signaling, positioning TAGs as key determinants of plant resilience and promising targets for the biotechnological enhancement of crop stress tolerance.