Dataset Information

Larbat2016.3 - Modeling the diversion of primary carbon flux into secondary metabolism under variable nitrate and light or dark conditions (Light Dark Cycles with Minimum Starch Adaption)

ABSTRACT: This is a global mathematical model describing metabolic partitioning of carbon resources in plants between growth and defense, as a function of nitrate fertilization. The model hinges on the dynamics of sucrose inflow/outflow properties. The model also accounts for variations in photosynthetic activity as dictated by a daily light/dark cycle. Furthermore, the adaptive changes in starch metabolism that occur with changing light durations (short days vs long days) are also investigated.

SUBMITTER: Johannes Meyer

PROVIDER: BIOMD0000000859 | BioModels | 2019-11-13

REPOSITORIES: BioModels

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Publications

Modeling the diversion of primary carbon flux into secondary metabolism under variable nitrate and light/dark conditions.

Larbat Romain R Robin Christophe C Lillo Cathrine C Drengstig Tormod T Ruoff Peter P

Journal of theoretical biology 20160506

In plants, the partitioning of carbon resources between growth and defense is detrimental for their development. From a metabolic viewpoint, growth is mainly related to primary metabolism including protein, amino acid and lipid synthesis, whereas defense is based notably on the biosynthesis of a myriad of secondary metabolites. Environmental factors, such as nitrate fertilization, impact the partitioning of carbon resources between growth and defense. Indeed, experimental data showed that a shor ...[more]

PMID: 27164436

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Project description:The triose-phosphate/phosphate translocator (TPT) of the chloroplast inner envelope membrane mediates the counter-exchange of stromal triose phosphates derived from CO2 fixation with cytosolic phosphate, thus providing the cytosol with precursors for sucrose synthesis. We have isolated an Arabidopsis mutant (tpt-1) in which the gene encoding TPT is disrupted by a T-DNA insertion. During growth in low light tpt-1 plants are phenotypically normal, but in high light photosynthesis is inhibited and growth is retarded relative to wildtype. This mutant compensates for the absence of TPT by diverting photosynthate into starch which is hydrolysed and exported from the chloroplast as glucose that is subsequently phosphorylated by hexokinase. In low light the capacity of the pathway of starch synthesis is sufficient to accommodate the normal rate of CO2 fixation, but in high light it is unable to match the potential rate of CO2 fixation. Consequently, in high light-grown plants there are measurable effects on the redoxstate of several components. Thus, the tpt-1 mutation influences the carbohydrate status within the cell, alters the form in which carbon is received by the cytosol, and changes the redox signals that are important in photosynthetic acclimation. Method: Plants will be grown in a 8h light:16h dark regime at both 400 and 100 Âµmol PAR m-2 s-1. Total RNA will be extracted from pools of individual illuminated leaves from at least eight plants at growth stage 3.70. Leaves will be harvested 2 h into the photoperiod to maximise differences between plant lines in the expression of genes of photosynthesis and carbohydrate metabolism. We anticipate that expression of many genes will be affected by the absence of TPT and by changes in light intensity. However, by comparing differences in transcript levels between wildtype and TPT mutant grown in high light with the differences that occur in plants grown in low light we will discriminate between genes whose expression is affected by changes in the pattern of carbohydrate metabolism and those influenced by redox poise of the thylakoid photochemical components. These comparisons will also highlight genes affected by recently identified regulatory interactions between sugar-sensing and redox-sensing. A genome-wide expression study will establish the extent to which gene expression is altered by the absence of TPT in leaves, and will provide the basis for more detailed analysis of a selected range of transcripts whose levels of expression differ between plant lines.

Dataset Information

Larbat2016.3 - Modeling the diversion of primary carbon flux into secondary metabolism under variable nitrate and light or dark conditions (Light Dark Cycles with Minimum Starch Adaption)

Publications

Modeling the diversion of primary carbon flux into secondary metabolism under variable nitrate and light/dark conditions.

Similar Datasets

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