Abstract
The aim of this work was to use tubers from transgenic lines of potato (Solanum tuberosum) containing increased amounts of ADPglucose pyrophosphorylase to study the role of this enzyme in the control of starch synthesis. A 4-5-fold increase in activity of the enzyme, achieved by transformation with the Escherichia coli ADPglucose pyrophosphorylase gene glgC-16, had no detectable effect on the starch content of developing or mature tubers. No significant effects were found on the contents of ADPglucose, UDPglucose, glucose 1-phosphate, glucose 6-phosphate, PP1, ATP and ADP. Flux from [U-14C]sucrose, supplied to tubers still attached to the plant, to starch increased roughly in proportion to the increase in ADPglucose pyrophosphorylase activity. These measurements of flux gave a response coefficient close to 1 for the activity of the pyrophosphorylase in respect of starch synthesis. Pulse-chase experiments with [U-14C]sucrose showed that the increased flux into starch in the transformed tubers was accompanied by an increased rate of starch turnover. Further experiments suggested that the increased turnover was associated with an increase in the capacity of the tubers to degrade starch.
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Claims 7
Claim · model-written summary
The transformation raised ADPglucose pyrophosphorylase activity 4-5-fold.
- Taxon
- potato
Solanum tuberosumt0 - Treatment
- transformation with the Escherichia coli ADPglucose pyrophosphorylase gene glgC-16e0
- Gene
- Escherichia coli ADPglucose pyrophosphorylase gene glgC-16e0
- Outcome
- activity of the enzymee0
- Direction
- increasee0
- Value
- 4-5-folde0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A 4-5-fold increase in activity of the enzyme, achieved by transformation with the Escherichia coli ADPglucose pyrophosphorylase gene glgC-16”
t0“potato (Solanum tuberosum)”
Claim · model-written summary
Increased enzyme activity had no detectable effect on starch content of developing or mature tubers.
- Taxon
- potatoSolanum tuberosumt0
- Treatment
- transformation with the Escherichia coli ADPglucose pyrophosphorylase gene glgC-16e0
- Gene
- Escherichia coli ADPglucose pyrophosphorylase gene glgC-16e0
- Outcome
- starch content of developing or mature tuberse0
- Direction
- no detectable effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A 4-5-fold increase in activity of the enzyme, achieved by transformation with the Escherichia coli ADPglucose pyrophosphorylase gene glgC-16, had no detectable effect on the starch content of developing or mature tubers.”
t0“potato (Solanum tuberosum)”
Claim · model-written summary
The increased enzyme activity had no significant effect on the measured nucleotide sugar and phosphate metabolite contents.
- Taxon
- potatoSolanum tuberosumt0
- Treatment
- increased ADPglucose pyrophosphorylaset0
- Outcome
- contents of ADPglucose, UDPglucose, glucose 1-phosphate, glucose 6-phosphate, PP1, ATP and ADPe0
- Direction
- No significant effectse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“No significant effects were found on the contents of ADPglucose, UDPglucose, glucose 1-phosphate, glucose 6-phosphate, PP1, ATP and ADP.”
t0“potato (Solanum tuberosum) with increased ADPglucose pyrophosphorylase”
Claim · model-written summary
Flux from supplied sucrose to starch rose roughly with enzyme activity.
- Taxon
- potatoSolanum tuberosumt0
- Gene
- ADPglucose pyrophosphorylasee0
- Outcome
- Flux from [U-14C]sucrose, supplied to tubers still attached to the plant, to starche0
- Direction
- increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Flux from [U-14C]sucrose, supplied to tubers still attached to the plant, to starch increased roughly in proportion to the increase in ADPglucose pyrophosphorylase activity.”
t0“potato (Solanum tuberosum)”
Claim · model-written summary
Flux measurements gave a response coefficient close to 1 for starch synthesis against enzyme activity.
- Taxon
- potatoSolanum tuberosumt0
- Gene
- pyrophosphorylasee0
- Outcome
- response coefficiente0
- Value
- close to 1e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“These measurements of flux gave a response coefficient close to 1 for the activity of the pyrophosphorylase in respect of starch synthesis.”
t0“potato (Solanum tuberosum)”
Claim · model-written summary
Transformed tubers with increased starch flux had increased starch turnover.
- Taxon
- potatoSolanum tuberosumt0
- Material
- transformed tuberse0
- Outcome
- rate of starch turnovere0
- Direction
- increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the increased flux into starch in the transformed tubers was accompanied by an increased rate of starch turnover.”
t0“potato (Solanum tuberosum)”
Claim · model-written summary
Increased turnover was associated with greater tuber starch degradation capacity.
- Taxon
- potatoSolanum tuberosumt0
- Organ / stage
- tuberse0
- Outcome
- capacity of the tubers to degrade starche0
- Direction
- increasee0
- Qualifier
- increased turnovere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the increased turnover was associated with an increase in the capacity of the tubers to degrade starch.”
t0“potato (Solanum tuberosum)”
The same questions in other papers
transgenic · physiology: enzyme activity · Solanum tuberosum (potato)Positive and negative results
1 paper in the same direction as this paper · 2 in the opposite direction
- no effect
- negative
- positive
transgenic · quality: sugar starch · Solanum tuberosum (potato)Positive and negative results
11 papers in the same direction as this paper · 2 in the opposite direction
- positive
- positive
- negative
10 papers more in this group
See all 14 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.