Lipid trafficking and signaling in plants

Lipids are essential to proper cell structure, function, and signaling during development and in response to biotic and abiotic stresses in all organisms, including plants. The acquisition of plant-specific organelles, in particular the chloroplast with its extensive photosynthetic membranes, led to the manifestation of unique plant lipids. The cooperation of lipid biosynthetic pathways in the endoplasmic reticulum and the chloroplast necessitate transport of precursors and intermediates between the two organelles. In addition to their structural functions in membranes, lipids in plants are also involved in many signaling mechanisms that influence development and stress responses. Here, we briefly review key aspects of plant lipid biosynthesis and trafficking, and focus on lipid signaling in plants. Emphasis is on the central role of phosphatidic acid as an essential lipid precursor and signal lipid for development as well as abiotic and biotic stress responses. Finally, we discuss a novel long-distance, lipid-mediated signaling mechanism for systemic stress response in plants.