Spatiotemporal organization of key enzymatic steps mediating plant oil biogenesis and seed filling

Seed oils are a valuable commodity and a wide range of "oil seed crops", such as rapeseed, linseed, sunflower or soybean, have agricultural relevance. Most oil-seed crops deposit oils consisting of triacylglycerol (TAG), in which three fatty acids are esterified to a glycerol backbone. Based on genetic studies on the well-established oil-seed model, Arabidopsis thaliana, most enzymes and corresponding genes involved in biosynthesis and modification of fatty acids and their incorporation into TAG were previously identified. Even though the enzymes are known, there is still a substantial lack of information about their subcellular distribution, in particular with regard to the precise in vivo localization patterns of the enzymes in membrane microdomains. The aim of this project is to systematically analyze the subcellular distribution of functional fluorescent fusions of key enzymes of fatty acid metabolism and TAG biogenesis during Arabidopsis seed filling. Particular consideration will be given i) the characterization of relevant membrane subdomains of the endoplasmic reticulum (ER) in vivo; ii) to the dynamic spatiotemporal relations of different enzymes and their interactions, and iii) to the identification of molecular determinants mediating subcellular localization. The study will take advantage of state-of-the-art high-resolution live-imaging techniques and quantitative image analysis, as well as Arabidopsis and yeast genetic resources and comprehensive biochemical analysis. The outcome of the proposed studies will provide important new information on the biology of oil deposition in seeds, which may help to circumvent current bottlenecks in the metabolic engineering of designer seed oils in crop plants in the future.