Abstract
Here we investigate the role of hexoses in the metabolism of the developing potato (Solanum tuberosum) tuber by the expression of a bacterial xylose isomerase which catalyzes the interconversion of glucose and fructose. Previously, we found that glycolysis was induced in transgenic tubers expressing a yeast invertase in the cytosol and postulated that this was due either to the decreased levels of sucrose or to effects downstream of the sucrose cleavage. In the present study xylose isomerase was expressed under the control of the tuber-specific patatin promoter. Selected transformants exhibited minor changes in the levels of tuber glucose and fructose but not in sucrose. Analysis of the enzyme activities of the glycolytic pathway revealed minor yet significant increases in the maximal catalytic activities of aldolase and glyceraldehyde 3-phosphate dehydrogenase but no increase in the activities of other enzymes of glycolysis. These lines were also characterized by an elevated tuber number, glycolytic and sucrose synthetic fluxes and in some metabolite levels downstream of glycolysis. When considered together these data suggest that the perturbation of hexose levels can result in increased glycolytic and sucrose (re)synthetic fluxes in the potato tuber even in the absence of changes in the level of sucrose. The consequences of altering hexose levels in the tuber are, however, not as severe as those observed following perturbation of the level of tuber sucrose.
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Claims 8
Claim · model-written summary
Transformants showed minor tuber glucose and fructose changes.
- Taxon
- potato
Solanum tuberosumt0 - Treatment
- Selected transformantse0
- Outcome
- levels of tuber glucose and fructosee0
- Direction
- changese0
- Qualifier
- minore0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Selected transformants exhibited minor changes in the levels of tuber glucose and fructose but not in sucrose”
t0“potato”
Claim · model-written summary
Transformants showed no change in sucrose level.
- Taxon
- potatoSolanum tuberosumt0
- Treatment
- Selected transformantse0
- Outcome
- sucrosee0
- Direction
- but note0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Selected transformants exhibited minor changes in the levels of tuber glucose and fructose but not in sucrose”
t0“potato”
Claim · model-written summary
Aldolase maximal catalytic activity increased slightly but significantly.
- Taxon
- potatoSolanum tuberosumt0
- Treatment
- xylose isomeraset0
- Outcome
- maximal catalytic activities of aldolasee0
- Direction
- increasese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“minor yet significant increases in the maximal catalytic activities of aldolase and glyceraldehyde 3-phosphate dehydrogenase”
t0“Xylose Isomerase in Potato Tubers”
Claim · model-written summary
Glyceraldehyde 3-phosphate dehydrogenase maximal catalytic activity increased slightly but significantly.
- Taxon
- PotatoSolanum tuberosumt0
- Treatment
- Xylose Isomeraset0
- Outcome
- maximal catalytic activities of aldolase and glyceraldehyde 3-phosphate dehydrogenasee0
- Direction
- increasese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“minor yet significant increases in the maximal catalytic activities of aldolase and glyceraldehyde 3-phosphate dehydrogenase”
t0“Xylose Isomerase in Potato Tubers”
Claim · model-written summary
Other glycolytic enzyme activities did not increase.
- Taxon
- PotatoSolanum tuberosumt0
- Treatment
- Xylose Isomeraset0
- Outcome
- activities of other enzymes of glycolysise0
- Direction
- no increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“no increase in the activities of other enzymes of glycolysis”
t0“Xylose Isomerase in Potato Tubers”
Claim · model-written summary
Transgenic lines had elevated tuber number.
- Taxon
- PotatoSolanum tuberosumt0
- Outcome
- tuber numbere0
- Direction
- elevatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“These lines were also characterized by an elevated tuber number, glycolytic and sucrose synthetic fluxes and in some metabolite levels downstream of glycolysis”
t0“Potato Tubers”
Claim · model-written summary
Transgenic lines had elevated glycolytic and sucrose synthetic fluxes.
- Taxon
- PotatoSolanum tuberosumt0
- Outcome
- glycolytic and sucrose synthetic fluxese0
- Direction
- elevatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“These lines were also characterized by an elevated tuber number, glycolytic and sucrose synthetic fluxes and in some metabolite levels downstream of glycolysis”
t0“Potato Tubers”
Claim · model-written summary
Transgenic lines had elevated levels of some downstream glycolytic metabolites.
- Taxon
- PotatoSolanum tuberosumt0
- Outcome
- some metabolite levels downstream of glycolysise0
- Direction
- elevatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“These lines were also characterized by an elevated tuber number, glycolytic and sucrose synthetic fluxes and in some metabolite levels downstream of glycolysis”
t0“Potato Tubers”
The same questions in other papers
transgenic · molecular: metabolites · Solanum tuberosum (potato)Positive and negative results
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- positive
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See all 10 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.