In vivo 13C NMR determines metabolic fluxes and steady state in linseed embryos.
The dynamics of developing linseed embryo metabolism was investigated using (13)C-labelling experiments where the real-time kinetics of label incorporation into metabolites was monitored in situ using in vivo NMR. The approach took advantage of the occurrence in this plant tissue of large metabolite pools - such as sucrose or lipids - to provide direct and quantitative measurement of the evolution of the labelling state within central metabolism. As a pre-requisite for the use of steady state flux measurements it was shown that isotopic steady state was reached within 3 h at the level of central intermediates whereas it took a further 6h for the sucrose pool. Complete isotopic and metabolic steady state took 18 h to be reached. The data collected during the transient state where label was equilibrated but the metabolic steady state was incomplete, enabled the rates of lipid and sucrose synthesis to be measured in situ on the same sample. This approach is suitable to get a direct assessment of metabolic time-scales within living plant tissues and provides a valuable complement to steady state flux determinations.
Troufflard
Stéphanie
S
Génie Enzymatique et Cellulaire, UMR-CNRS 6022, Université de Picardie Jules Verne, 33 Rue St-Leu, 80039 Amiens, France.
Roscher
Albrecht
A
Thomasset
Brigitte
B
Barbotin
Jean-Noël
JN
Rawsthorne
Stephen
S
Portais
Jean-Charles
JC
D002247:Carbon Isotopes; D019597:Flax / Q000196:embryology* / Q000378:metabolism; D007700:Kinetics; D008055:Lipids / Q000096:biosynthesis / Q000737:chemistry; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods; D012639:Seeds / Q000378:metabolism*; D013395:Sucrose / Q000737:chemistry / Q000378:metabolism; D013997:Time Factors
D002247:Carbon Isotopes; D008055:Lipids; D013395:Sucrose