Data from: Model-assisted analysis of sugar metabolism throughout tomato fruit development reveals enzyme and carrier properties in relation to vacuole expansion
Data files
Aug 05, 2015 version files 1.72 MB
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Beauvoit et al._tomato fruit sugar model_high affinity_15dpa.cps
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Beauvoit et al._tomato fruit sugar model_high affinity_22dpa.cps
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Beauvoit et al._tomato fruit sugar model_high affinity_27dpa.cps
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Beauvoit et al._tomato fruit sugar model_high affinity_30 dpa.cps
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Beauvoit et al._tomato fruit sugar model_high affinity_35dpa.cps
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Beauvoit et al._tomato fruit sugar model_high affinity_40dpa.cps
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Beauvoit et al._tomato fruit sugar model_high affinity_44 dpa.cps
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Beauvoit et al._tomato fruit sugar model_high affinity_47 dpa.cps
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Beauvoit et al._tomato fruit sugar model_high affinity_4dpa.cps
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Beauvoit et al._tomato fruit sugar model_high affinity_8dpa.cps
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Abstract
A kinetic model combining enzyme activity measurements and subcellular compartmentation was parameterized to fit the sucrose, hexose, and glucose-6-P contents of pericarp throughout tomato (Solanum lycopersicum) fruit development. The model was further validated using independent data obtained from domesticated and wild tomato species and on transgenic lines. A hierarchical clustering analysis of the calculated fluxes and enzyme capacities together revealed stage-dependent features. Cell division was characterized by a high sucrolytic activity of the vacuole, whereas sucrose cleavage during expansion was sustained by both sucrose synthase and neutral invertase, associated with minimal futile cycling. Most importantly, a tight correlation between flux rate and enzyme capacity was found for fructokinase and PPi-dependent phosphofructokinase during cell division and for sucrose synthase, UDP-glucopyrophosphorylase, and phosphoglucomutase during expansion, thus suggesting an adaptation of enzyme abundance to metabolic needs. In contrast, for most enzymes, flux rates varied irrespectively of enzyme capacities, and most enzymes functioned at <5% of their maximal catalytic capacity. One of the major findings with the model was the high accumulation of soluble sugars within the vacuole together with organic acids, thus enabling the osmotic-driven vacuole expansion that was found during cell division.