Seeds provide most of the dietary calories consumed in the world and are the major economic value of agricultural crops. In order to rationally engineer the storage products of seeds (oil, protein and starch) we need to understand the fluxes through the network of core metabolism. Studies on gene expression patterns and the enzymes present during seed development are able to provide the "parts list" available to carry out metabolism but are short of being able to quantitatively define the in vivo conversion rates of enzymes. Therefore a main interest of my research is the advancement of methods for the analysis of the central carbon metabolism network in plants in particular using stable-isotope labeling. Metabolic flux analysis (MFA) by this approach has been important in understanding and engineering the metabolism of microorganisms in recent years, and it should be of increasing importance in plant research in the near future.

My research is focused on metabolic flux analysis and pathway analysis in plants by employing labeling experiments, mathematical models and computer simulation to describe and analyze metabolism quantitatively. In particular I use steady-state stable isotope labeling to determine flux ratios through branch points of metabolism. Brassica napus Embryos are labeled with a variety of 13C-labeled precursors and individual C-atoms are traced through the metabolic network by analyzing the label in metabolites and end products by GC/MS and NMR. This methodology can investigate fluxes in vivo in systems unperturbed by cell disruption, mutation or transgenes. A particular challenge in plants is the sub-cellular compartmentation of enzymes and substrates.