Lipid-mediated responses to nutrient and other stresses: Roles in plant adaptation and signaling

Abstract Lipids are essential components of biological membranes; however, their roles in plants go far beyond providing structural support. They are actively involved in signaling and metabolic regulation during abiotic and biotic stress. Plants use lipid-based strategies to adapt to nutrient shortages, toxic conditions, and changing environments. Signaling lipids such as phosphatidic acid (PA), phosphoinositides, sphingolipids, and oxylipins serve as molecular messengers that transmit stress signals to regulate ion transport, hormone interactions, and developmental flexibility. During nutrient deprivation, especially of phosphorus (P), nitrogen (N), and potassium (K), plants adjust membrane composition by replacing phospholipids with P-free glycolipids like galactolipids and sulfolipids, conserving critical nutrients while keeping membrane structure intact. Lipid intermediates, including PA, glycerol-3-phosphate, and negatively charged phospholipids, also act as secondary messengers in stress signaling networks. Lipid droplets and lipophagy help maintain carbon and redox balance, while enzymes like phospholipases and glycerophosphodiesterases recycle nutrients and alter lipid profiles. Under K deficiency and toxic metal exposure (e.g., aluminum (Al), cadmium (Cd)), lipid turnover influences membrane stability, reactive oxygen species (ROS) production, and transporter function. Lipid modifications also reduce toxic ion binding and cellular damage, and molecules derived from lipids, such as jasmonates, play roles in secondary metabolism and hormonal defense pathways. Although lipid-based stress responses are conserved throughout plant lineages, the regulatory mechanisms controlling lipid fluxes are not yet fully understood. New tools, like genetically coded lipid biosensors and lipidomics platforms, are uncovering the spatial and temporal dynamics of lipid signaling with unprecedented detail. Improving our understanding of lipid-mediated stress responses may enable the development of crops with better nutrient efficiency and resilience to climatic and edaphic stresses, contributing to sustainable agriculture.