Abstract
ABSTRACT Sugars are not only metabolic substrates: they also act as signals that regulate the metabolism of plants. Previously, we found that glycolysis is induced in transgenic tubers expressing a yeast invertase in the cytosol but not in those expressing invertase in the apoplast. This suggests that either the low level of sucrose, the increased formation of cytosolic glucose or the increased levels of metabolites downstream of the sucrose cleavage is responsible for the induction of glycolysis in storage organs. In order to discriminate between these possibilities, we cloned and expressed a bacterial sucrose phosphorylase gene from Pseudomonas saccharophila in potato tubers. Due to the phosphorolytic cleavage of sucrose, formation of glucose was circumvented, thus allowing assessment of the importance of cytosolic glucose – and, by implication, flux through hexokinase – in glycolytic induction. Expression of sucrose phosphorylase led to: (i) a decrease in sucrose content, but no decrease in glucose or fructose; (ii) a decrease in both starch accumulation and tuber yield; (iii) increased levels of glycolytic metabolites; (iv) an induction of the activities of key enzymes of glycolysis; and (v) increased respiratory activity. We conclude that the induction of glycolysis in heterotrophic tissues such as potato tubers occurs via a glucose‐independent mechanism.
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Claims 7
Claim · model-written summary
Sucrose phosphorylase expression decreased sucrose content.
- Taxon
- potato
Solanum tuberosumt0 - Treatment
- Expression of sucrose phosphorylasee0
- Outcome
- sucrose contente0
- Direction
- decreasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Expression of sucrose phosphorylase led to: (i) a decrease in sucrose content, but no decrease in glucose or fructose”
t0“potato tubers”
Claim · model-written summary
Sucrose phosphorylase expression did not decrease glucose or fructose.
- Taxon
- potatoSolanum tuberosumt0
- Treatment
- Expression of sucrose phosphorylasee0
- Outcome
- glucose or fructosee0
- Direction
- no decreasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Expression of sucrose phosphorylase led to: (i) a decrease in sucrose content, but no decrease in glucose or fructose”
t0“potato tubers”
Claim · model-written summary
Sucrose phosphorylase expression decreased starch accumulation and tuber yield.
- Taxon
- potatoSolanum tuberosumt0
- Treatment
- Expression of sucrose phosphorylasee0
- Outcome
- starch accumulation and tuber yielde0
- Direction
- decreasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Expression of sucrose phosphorylase led to: (i) a decrease in sucrose content, but no decrease in glucose or fructose; (ii) a decrease in both starch accumulation and tuber yield”
t0“potato tubers”
Claim · model-written summary
Sucrose phosphorylase expression increased glycolytic metabolite levels.
- Taxon
- potatoSolanum tuberosumt0
- Treatment
- Expression of sucrose phosphorylasee0
- Outcome
- levels of glycolytic metabolitese0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Expression of sucrose phosphorylase led to: (i) a decrease in sucrose content, but no decrease in glucose or fructose; (ii) a decrease in both starch accumulation and tuber yield; (iii) increased levels of glycolytic metabolites”
t0“potato tubers”
Claim · model-written summary
Sucrose phosphorylase expression induced key glycolytic enzyme activities.
- Taxon
- potatoSolanum tuberosumt0
- Treatment
- Expression of sucrose phosphorylasee0
- Outcome
- activities of key enzymes of glycolysise0
- Direction
- inductione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Expression of sucrose phosphorylase led to: (i) a decrease in sucrose content, but no decrease in glucose or fructose; (ii) a decrease in both starch accumulation and tuber yield; (iii) increased levels of glycolytic metabolites; (iv) an induction of the activities of key enzymes of glycolysis”
t0“potato tubers”
Claim · model-written summary
Sucrose phosphorylase expression increased respiration.
- Taxon
- potatoSolanum tuberosumt0
- Treatment
- Expression of sucrose phosphorylasee0
- Outcome
- respiratory activitye0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Expression of sucrose phosphorylase led to: (i) a decrease in sucrose content, but no decrease in glucose or fructose; (ii) a decrease in both starch accumulation and tuber yield; (iii) increased levels of glycolytic metabolites; (iv) an induction of the activities of key enzymes of glycolysis; and (v) increased respiratory activity”
t0“potato tubers”
Claim · model-written summary
Glycolysis induction in potato tubers occurs through a glucose-independent mechanism.
- Taxon
- potatoSolanum tuberosume0
- Outcome
- induction of glycolysise0
- Qualifier
- glucose‐independent mechanisme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the induction of glycolysis in heterotrophic tissues such as potato tubers occurs via a glucose‐independent mechanism”
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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.