Acclimation of metabolism to light in Arabidopsis thaliana: the glucose 6-phosphate/phosphate translocator GPT2 directs metabolic acclimation.
Mature leaves of plants transferred from low to high light typically increase their photosynthetic capacity. In Arabidopsis thaliana, this dynamic acclimation requires expression of GPT2, a glucose 6-phosphate/phosphate translocator. Here, we examine the impact of GPT2 on leaf metabolism and photosynthesis. Plants of wild type and of a GPT2 knockout (gpt2.2) grown under low light achieved the same photosynthetic rate despite having different metabolic and transcriptomic strategies. Immediately upon transfer to high light, gpt2.2 plants showed a higher rate of photosynthesis than wild-type plants (35%); however, over subsequent days, wild-type plants acclimated photosynthetic capacity, increasing the photosynthesis rate by 100% after 7 d. Wild-type plants accumulated more starch than gpt2.2 plants throughout acclimation. We suggest that GPT2 activity results in the net import of glucose 6-phosphate from cytosol to chloroplast, increasing starch synthesis. There was clear acclimation of metabolism, with short-term changes typically being reversed as plants acclimated. Distinct responses to light were observed in wild-type and gpt2.2 leaves. Significantly higher levels of sugar phosphates were observed in gpt2.2. We suggest that GPT2 alters the distribution of metabolites between compartments and that this plays an essential role in allowing the cell to interpret environmental signals.
['Dyson|Beth C|BC|', 'Allwood|J William|JW|', 'Feil|Regina|R|', 'Xu|Yun|Y|', 'Miller|Matthew|M|', 'Bowsher|Caroline G|CG|', 'Goodacre|Royston|R|', 'Lunn|John E|JE|', 'Johnson|Giles N|GN|']
D000064:Acclimatization D017360:Arabidopsis D029681:Arabidopsis Proteins D002736:Chloroplasts D018506:Gene Expression Regulation, Plant D055786:Gene Knockout Techniques D019298:Glucose-6-Phosphate D008027:Light D009004:Monosaccharide Transport Proteins D009154:Mutation D010788:Photosynthesis D018515:Plant Leaves D030821:Plants, Genetically Modified D013213:Starch
high light photosynthesis sugar signalling