RT Journal Article
SR Electronic
T1 Predicting metabolism during growth by osmotic cell expansion
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 731232
DO 10.1101/731232
A1 Sanu Shameer
A1 José G. Vallarino
A1 Alisdair R. Fernie
A1 R. George Ratcliffe
A1 Lee J Sweetlove
YR 2019
UL http://biorxiv.org/content/early/2019/08/12/731232.abstract
AB Cell expansion is a significant contributor to organ growth and is driven by the accumulation of osmolytes to increase cell turgor pressure. Metabolic modelling has the potential to provide insights into the processes that underpin osmolyte synthesis and transport, but the main computational approach for predicting metabolic network fluxes, flux balance analysis (FBA), typically uses biomass composition as the main output constraint and ignores potential changes in cell volume. Here we present GrOE-FBA (Growth by Osmotic Expansion-Flux Balance Analysis), a framework that accounts for both the metabolic and ionic contributions to the osmotica that drive cell expansion, as well as the synthesis of protein, cell wall and cell membrane components required for cell enlargement. Using GrOE-FBA, the metabolic fluxes in dividing and expanding cell were analyzed, and the energetic costs for metabolite biosynthesis and accumulation in the two scenarios were found to be surprisingly similar. The expansion phase of tomato fruit growth was also modelled using a multi-phase single optimization GrOE-FBA model and this approach gave accurate predictions of the major metabolite levels throughout fruit development as well as revealing a role for transitory starch accumulation in ensuring optimal fruit development.