title: Transcript abundance on its own cannot be used to infer fluxes in central metabolism.
abstract: An attempt has been made to define the extent to which metabolic flux in central plant metabolism is reflected by changes in the transcriptome and metabolome, based on an analysis of in vitro cultured immature embryos of two oilseed rape (Brassica napus) accessions which contrast for seed lipid accumulation. Metabolic flux analysis (MFA) was used to constrain a flux balance metabolic model which included 671 biochemical and transport reactions within the central metabolism. This highly confident flux information was eventually used for comparative analysis of flux vs. transcript (metabolite). Metabolite profiling succeeded in identifying 79 intermediates within the central metabolism, some of which differed quantitatively between the two accessions and displayed a significant shift corresponding to flux. An RNA-Seq based transcriptome analysis revealed a large number of genes which were differentially transcribed in the two accessions, including some enzymes/proteins active in major metabolic pathways. With a few exceptions, differential activity in the major pathways (glycolysis, TCA cycle, amino acid, and fatty acid synthesis) was not reflected in contrasting abundances of the relevant transcripts. The conclusion was that transcript abundance on its own cannot be used to infer metabolic activity/fluxes in central plant metabolism. This limitation needs to be borne in mind in evaluating transcriptome data and designing metabolic engineering experiments.
authors.affiliation: Brookhaven National Laboratory, Department of Biological, Environmental and Climate Sciences Upton, NY, USA.
authors.forename: Jörg
authors.initials: J
authors.lastname: Schwender
authors.affiliation: Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung Gatersleben, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: König
authors.affiliation: Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung Gatersleben, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Klapperstück
authors.affiliation: Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung Gatersleben, Germany.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Heinzel
authors.affiliation: Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung Gatersleben, Germany ; University of Würzburg, Institute of Experimental Physics 5 Würzburg, Germany.
authors.forename: Eberhard
authors.initials: E
authors.lastname: Munz
authors.affiliation: Brookhaven National Laboratory, Department of Biological, Environmental and Climate Sciences Upton, NY, USA.
authors.forename: Inga
authors.initials: I
authors.lastname: Hebbelmann
authors.affiliation: Brookhaven National Laboratory, Department of Biological, Environmental and Climate Sciences Upton, NY, USA.
authors.forename: Jordan O
authors.initials: JO
authors.lastname: Hay
authors.affiliation: Bayer CropScience NV, Trait Research Zwijnaarde, Belgium.
authors.forename: Peter
authors.initials: P
authors.lastname: Denolf
authors.affiliation: Bayer CropScience NV, Trait Research Zwijnaarde, Belgium.
authors.forename: Stefanie
authors.initials: S
authors.lastname: De Bodt
authors.affiliation: Bayer CropScience NV, Trait Research Zwijnaarde, Belgium.
authors.forename: Henning
authors.initials: H
authors.lastname: Redestig
authors.affiliation: Bayer CropScience NV, Trait Research Zwijnaarde, Belgium.
authors.forename: Evelyne
authors.initials: E
authors.lastname: Caestecker
authors.affiliation: University of Würzburg, Institute of Experimental Physics 5 Würzburg, Germany.
authors.forename: Peter M
authors.initials: PM
authors.lastname: Jakob
authors.affiliation: Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung Gatersleben, Germany.
authors.forename: Ljudmilla
authors.initials: L
authors.lastname: Borisjuk
authors.affiliation: Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung Gatersleben, Germany.
authors.forename: Hardy
authors.initials: H
authors.lastname: Rolletschek
keywords: 13C-metabolic flux analysis; Brassica napus; central metabolism; flux balance analysis; lipid biosynthesis; oilseeds; targeted metabolite profiling