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Series GSE5737

Query DataSets for GSE5737

Status

Public on Jan 08, 2007

Title

Carbohydrate- and redox-regulation of gene expression in a TPT mutant

Organism

Arabidopsis thaliana

Experiment type

Expression profiling by array

Summary

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.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 maximises 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.

Experimenter name = Robin Walters
Experimenter phone = 01865 275000
Experimenter fax = 01865 275074
Experimenter address = Dept of Plant Sciences
Experimenter address = University of Oxford
Experimenter address = South Parks Road
Experimenter address = Oxford
Experimenter zip/postal_code = OX1 3RB
Experimenter country = UK
Keywords: growth_condition_design; genetic_modification_design;

Overall design

12 samples were used in this experiment

Contributor(s)

Walters R, Kruger N, Townsend H, Emmerson Z, Schildknecht B

Citation missing

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Submission date

Sep 01, 2006

Last update date

Aug 28, 2018

Contact name

Nottingham Arabidopsis Stock Centre (NASC)