Quantitative multilevel analysis of central metabolism in developing oilseeds of oilseed rape during in vitro culture
Creators: name: Schwender, Jörg
name: Hebbelmann, Inga
name: Heinzel, Nicolas
name: Hildebrandt, Tatjana
name: Rogers, Alistair
name: Naik, Dhiraj
name: Klapperstück, Matthias
name: Braun, Hans-Peter
name: Schreiber, Falk
name: Denolf, Peter
name: Borisjuk, Ljudmilla
name: Rolletschek, Hardy
Publisher: name: Rockville, Md. : American Society of Plant Physiologists
Year: 2015
Subjects: subject: Brassica napus
subject: amino acid
subject: carbon
subject: plant protein
subject: proteome
subject: starch
subject: vegetable oil
subject: biocatalysis
subject: biological model
subject: biomass
subject: carbohydrate metabolism
subject: embryology
subject: glycolysis
subject: lipid metabolism
subject: liquid chromatography
subject: mass spectrometry
subject: metabolic flux analysis
subject: metabolism
subject: multilevel analysis
subject: plant seed
subject: procedures
subject: rapeseed
subject: time factor
subject: tissue culture technique
subject: ultrastructure
subject: Amino Acids
subject: Biocatalysis
subject: Biomass
subject: Carbohydrate Metabolism
subject: Carbon
subject: Chromatography, Liquid
subject: Glycolysis
subject: Lipid Metabolism
subject: Mass Spectrometry
subject: Metabolic Flux Analysis
subject: Models, Biological
subject: Multilevel Analysis
subject: Plant Oils
subject: Plant Proteins
subject: Proteome
subject: Seeds
subject: Starch
subject: Time Factors
subject: Tissue Culture Techniques
subject: Dewey Decimal Classification::500 | Naturwissenschaften::580 | Pflanzen (Botanik)

description: Seeds provide the basis for many food, feed, and fuel products. Continued increases in seed yield, composition, and quality require an improved understanding of how the developing seed converts carbon and nitrogen supplies into storage. Current knowledge of this process is often based on the premise that transcriptional regulation directly translates via enzyme concentration into flux. In an attempt to highlight metabolic control, we explore genotypic differences in carbon partitioning for in vitro cultured developing embryos of oilseed rape (Brassica napus). We determined biomass composition as well as 79 net fluxes, the levels of 77 metabolites, and 26 enzyme activities with specific focus on central metabolism in nine selected germplasm accessions. Overall, we observed a tradeoff between the biomass component fractions of lipid and starch. With increasing lipid content over the spectrum of genotypes, plastidic fatty acid synthesis and glycolytic flux increased concomitantly, while glycolytic intermediates decreased. The lipid/starch tradeoff was not reflected at the proteome level, pointing to the significance of (posttranslational) metabolic control. Enzyme activity/flux and metabolite/flux correlations suggest that plastidic pyruvate kinase exerts flux control and that the lipid/starch tradeoff is most likely mediated by allosteric feedback regulation of phosphofructokinase and ADP-glucose pyrophosphorylase. Quantitative data were also used to calculate in vivo mass action ratios, reaction equilibria, and metabolite turnover times. Compounds like cyclic 39,59-AMP and sucrose-6-phosphate were identified to potentially be involved in so far unknown mechanisms of metabolic control. This study provides a rich source of quantitative data for those studying central metabolism.