Abstract
Sink strength of growing potato tubers is believed to be limited by sucrose metabolism and/or starch synthesis. Sucrose synthase (Susy) is most likely responsible for the entire sucrose cleavage in sink tubers, rather than invertases. To investigate the unique role of sucrose synthase with respect to sucrose metabolism and sink strength in growing potato tubers, transgenic potato plants were created expressing Susy antisense RNA corresponding to the T-type sucrose synthase isoform. Although the constitutive 35S CaMV promoter was used to drive the expression of the antisense RNA the inhibition of Susy activity was tuber-specific, indicating that independent Susy isoforms are responsible for Susy activity in different potato organs. The inhibition of Susy leads to no change in sucrose content, a strong accumulation of reducing sugars and an inhibition of starch accumulation in developing potato tubers. The increase in hexoses is paralleled by a 40-fold increase in invertase activities but no considerable changes in hexokinase activities. The reduction in starch accumulation is not due to an inhibition of the major starch biosynthetic enzymes. The changes in carbohydrate accumulation are accompanied by a decrease in total tuber dry weight and a reduction of soluble tuber proteins. The reduced protein accumulation is mainly due to a decrease in the major storage proteins patatin, the 22 kDa proteins and the proteinase inhibitors. The lowered accumulation of storage proteins is not a consequence of the availability of the free amino acid pool in potato tubers. Altogether these data are in agreement with the assumption that sucrose synthase is the major determinant of potato tuber sink strength. Contradictory to the hypothesis that the sink strength of growing potato tubers is inversely correlated with the tuber number per plant, no increase in tuber number per plant was found in Susy antisense plants.
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Claims 13
Claim · model-written summary
Inhibition of Susy activity in the antisense plants was tuber-specific.
- Taxon
- potato
Solanum tuberosumt0 - Organ / stage
- tubere0
- Outcome
- inhibition of Susy activitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the inhibition of Susy activity was tuber-specific”
t0“potato”
Claim · model-written summary
Susy inhibition caused no change in sucrose content in developing potato tubers.
- Taxon
- potatoSolanum tuberosumt0
- Organ / stage
- developing potato tuberse0
- Treatment
- inhibition of Susye0
- Outcome
- sucrose contente0
- Direction
- no changee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The inhibition of Susy leads to no change in sucrose content, a strong accumulation of reducing sugars and an inhibition of starch accumulation in developing potato tubers”
t0“potato”
Claim · model-written summary
Susy inhibition caused a strong accumulation of reducing sugars in developing potato tubers.
- Taxon
- potatoSolanum tuberosumt0
- Organ / stage
- developing potato tuberse0
- Treatment
- inhibition of Susye0
- Outcome
- reducing sugarse0
- Direction
- strong accumulatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The inhibition of Susy leads to no change in sucrose content, a strong accumulation of reducing sugars and an inhibition of starch accumulation in developing potato tubers”
t0“potato”
Claim · model-written summary
Susy inhibition inhibited starch accumulation in developing potato tubers.
- Taxon
- potatoSolanum tuberosumt0
- Organ / stage
- developing potato tuberse0
- Treatment
- inhibition of Susye0
- Outcome
- starch accumulatione0
- Direction
- inhibitione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The inhibition of Susy leads to no change in sucrose content, a strong accumulation of reducing sugars and an inhibition of starch accumulation in developing potato tubers”
t0“potato”
Claim · model-written summary
Invertase activities increased 40-fold in parallel with the increase in hexoses.
- Taxon
- potatoSolanum tuberosumt0
- Outcome
- invertase activitiese0
- Direction
- increasee0
- Value
- 40-folde0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The increase in hexoses is paralleled by a 40-fold increase in invertase activities”
t0“potato”
Claim · model-written summary
Hexokinase activities showed no considerable changes.
- Taxon
- potatoSolanum tuberosumt0
- Outcome
- hexokinase activitiese0
- Direction
- no considerable changese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“no considerable changes in hexokinase activities”
t0“potato”
Claim · model-written summary
The reduction in starch accumulation was not due to inhibition of the major starch biosynthetic enzymes.
- Taxon
- potatoSolanum tuberosumt0
- Outcome
- inhibition of the major starch biosynthetic enzymese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The reduction in starch accumulation is not due to an inhibition of the major starch biosynthetic enzymes”
t0“potato”
Claim · model-written summary
Total tuber dry weight decreased.
- Taxon
- potatoSolanum tuberosumt0
- Outcome
- total tuber dry weighte0
- Direction
- decreasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The changes in carbohydrate accumulation are accompanied by a decrease in total tuber dry weight and a reduction of soluble tuber proteins”
t0“potato”
Claim · model-written summary
Soluble tuber proteins were reduced.
- Taxon
- potatoSolanum tuberosumt0
- Outcome
- soluble tuber proteinse0
- Direction
- reductione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The changes in carbohydrate accumulation are accompanied by a decrease in total tuber dry weight and a reduction of soluble tuber proteins”
t0“potato”
Claim · model-written summary
The reduced protein accumulation was mainly due to a decrease in patatin, the 22 kDa proteins and the proteinase inhibitors.
- Taxon
- potatoSolanum tuberosumt0
- Outcome
- major storage proteins patatin, the 22 kDa proteins and the proteinase inhibitorse0
- Direction
- decreasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The reduced protein accumulation is mainly due to a decrease in the major storage proteins patatin, the 22 kDa proteins and the proteinase inhibitors”
t0“potato”
Claim · model-written summary
The lowered storage protein accumulation was not a consequence of the availability of the free amino acid pool in potato tubers.
- Taxon
- potatoSolanum tuberosumt0
- Outcome
- free amino acid poole0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The lowered accumulation of storage proteins is not a consequence of the availability of the free amino acid pool in potato tubers”
t0“potato”
Claim · model-written summary
Susy antisense plants showed no increase in tuber number per plant.
- Taxon
- potatoSolanum tuberosumt0
- Treatment
- Susy antisensee0
- Outcome
- tuber number per plante0
- Direction
- no increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“no increase in tuber number per plant was found in Susy antisense plants”
t0“potato”
Claim · model-written summary
The authors conclude that sucrose synthase is the major determinant of potato tuber sink strength.
- Taxon
- potatoSolanum tuberosumt0
- Gene
- sucrose synthasee0
- Outcome
- sink strengthe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Altogether these data are in agreement with the assumption that sucrose synthase is the major determinant of potato tuber sink strength”
t0“potato”
The same questions in other papers
loss of function · yield · Solanum tuberosum (potato)Positive and negative results
5 papers in the same direction as this paper · 4 in the opposite direction
- negative
- positive
- positive
6 papers more in this group
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.