Lipid Network Flux Cartography for Quantitative Control of Oil Accumulation and Composition

Washington State University, Pullman WA

Investigators

Abstract

Plant oils are a vital part of human life and are utilized as food, chemicals, and fuels. It is predicted that world output of plant oils must double by 2040 to meet the needs of the growing human population, and even larger increases are needed if plant oils will be used to increasingly replace petroleum as fuels and chemicals. To meet this rising demand we need a better understanding of the metabolic reactions that control plant oil biosynthesis and oil composition. The goal of this project is to quantitatively describe the control exerted by key oil and membrane lipid biosynthetic proteins over the flux of vital intermediates into either oils or membrane lipids in the model plant, Arabidopsis. To prepare the next generation workforce the PIs will incorporate their research into training of undergraduate and graduate students and a post-doctoral fellow. Since plant oils are valuable renewable resources used for food, fuels, and chemicals this research will further our ability to guide plant lipid metabolic networks for the production of designer oils. Little is known about what controls the flux of de novo diacylglycerol into alternative branches of the lipid biosynthetic network in different plant species. The PIs hypothesize that a crucial control point is the partitioning of de novo synthesized diacylglycerol between phosphatidylcholine and triacylglycerol synthesis. The aims of the research are: 1) deciphering the roles of the non-redundant diglyceride acetyltransferase 1 and diglyceride acetyltransferase 2 triacylglycerol synthesizing enzymes in partitioning of de novo diacylglycerol between direct oil production and membrane lipid synthesis; 2) characterize the role of phosphatidylcholine synthesis enzymes in partitioning of de novo diacylglycerol into different branches of the lipid biosynthetic network; 3) develop quantitative kinetic models for the control of glycerolipid fluxes in Arabidopsis; and 4) explore protein:protein interactions to characterize the molecular components that make up the lipid metabolic complexes that control diacylglycerol fluxes. The above approaches will be combined with computer modeling to produce a quantitative description of the control of metabolite fluxes through the plant lipid metabolic network that can then guide the production of designer plant oils.