Membrane lipids are essential components of all biological membranes and display two important functions. On one hand, they form lipophilic boundary surfaces thereby serving as diffusion barriers that separate cells from the environment and intracellular compartments from the cytosol. On the other hand, lipids may have essential functions as signals in developmental processes and in the interaction of cells with the environment. Lipid-based signal transduction processes in plants are in the focus of the research program of the research training group: In response to extracellular abiotic and biotic stresses, plants cells can activate lipid-based signal cascades that lead to a rapid and specific adaptation of the cell metabolism. Typically, lipid mediators can be generated from preformed membrane lipids by hydrolytic or oxidative processes and modulate via fast posttranslational and slow transcriptional regulation mechanisms plant responses involved in development, adaptation and senescence. A goal of current research is, to clarify the biosynthesis and regulation of lipid mediators as well as to characterize their mechanisms of action and function. In order to reach the goals of the research program, a close cooperation of biochemists (mass spectrometric analysis of lipid profiles and its dynamics (lipidomics)), biophysicists (experimental microscopy, membrane transport), molecular biologists (transcriptome analysis, generation and analysis of lipid biosynthesis and signal transduction mutants) and protein biochemists (proteome analysis) will be established. This cooperation involves groups from botanical, pharmaceutical, and biomedical divisions and will also form the basis for our teaching program in which we will present lipid-based signal transduction processes in the context of fundamental biological processes such as development, reproduction, stress adaptation and host defence.