Abstract
The aim of this work was to investigate the effect of decreased cytosolic pyruvate kinase (PKc) on potato (Solanum tuberosum) tuber metabolism. Transgenic potato plants with strongly reduced levels of PKc were generated by RNA interference gene silencing under the control of a tuber-specific promoter. Metabolite profiling showed that decreased PKc activity led to a decrease in the levels of pyruvate and some other organic acids involved in the tricarboxylic acid cycle. Flux analysis showed that this was accompanied by changes in carbon partitioning, with carbon flux being diverted from glycolysis toward starch synthesis. However, this metabolic shift was relatively small and hence did not result in enhanced starch levels in the tubers. Although total respiration rates and the ATP to ADP ratio were largely unchanged, transgenic tubers showed a strong decrease in the levels of alternative oxidase (AOX) protein and a corresponding decrease in the capacity of the alternative pathway of respiration. External feeding of pyruvate to tuber tissue or isolated mitochondria resulted in activation of the AOX pathway, both in the wild type and the PKc transgenic lines, providing direct evidence for the regulation of AOX by changes in pyruvate levels. Overall, these results provide evidence for a crucial role of PKc in the regulation of pyruvate levels as well as the level of the AOX in heterotrophic plant tissue, and furthermore reveal that these parameters are interlinked in vivo.
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Claims 8
Claim · model-written summary
Reduced PKc activity decreased pyruvate and other tricarboxylic acid cycle organic acids.
- Taxon
- potato
Solanum tuberosumt0 - Treatment
- decreased PKc activitye0
- Gene
- PKce0
- Outcome
- levels of pyruvate and some other organic acids involved in the tricarboxylic acid cyclee0
- Direction
- decreasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“decreased PKc activity led to a decrease in the levels of pyruvate and some other organic acids involved in the tricarboxylic acid cycle”
t0“Potato”
Claim · model-written summary
Carbon flux shifted from glycolysis toward starch synthesis.
- Taxon
- potatoSolanum tuberosumt0
- Treatment
- Decreased Expression of Cytosolic Pyruvate Kinaset0
- Outcome
- carbon fluxe0
- Direction
- divertede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“carbon flux being diverted from glycolysis toward starch synthesis”
t0“Decreased Expression of Cytosolic Pyruvate Kinase in Potato Tubers”
Claim · model-written summary
The metabolic shift did not enhance tuber starch levels.
- Taxon
- potatoSolanum tuberosumt0
- Treatment
- Decreased Expression of Cytosolic Pyruvate Kinaset0
- Outcome
- starch levels in the tuberse0
- Direction
- did not result in enhancede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“did not result in enhanced starch levels in the tubers”
t0“Decreased Expression of Cytosolic Pyruvate Kinase in Potato Tubers”
Claim · model-written summary
Total respiration rates and ATP to ADP ratio were largely unchanged.
- Taxon
- potatoSolanum tuberosumt0
- Outcome
- total respiration rates and the ATP to ADP ratioe0
- Direction
- largely unchangede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“total respiration rates and the ATP to ADP ratio were largely unchanged”
t0“Potato”
Claim · model-written summary
Transgenic tubers showed lower AOX protein.
- Taxon
- potatoSolanum tuberosumt0
- Material
- transgenic tuberse0
- Gene
- alternative oxidase (AOX) proteine0
- Outcome
- levels of alternative oxidase (AOX) proteine0
- Direction
- strong decreasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transgenic tubers showed a strong decrease in the levels of alternative oxidase (AOX) protein”
t0“Potato”
Claim · model-written summary
Transgenic tubers showed reduced alternative respiratory pathway capacity.
- Taxon
- potatoSolanum tuberosumt0
- Outcome
- capacity of the alternative pathway of respiratione0
- Direction
- decreasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a corresponding decrease in the capacity of the alternative pathway of respiration”
t0“Potato”
Claim · model-written summary
External pyruvate activated the AOX pathway in wild type tissue and PKc lines.
- Taxon
- potatoSolanum tuberosumt0
- Material
- wild type and the PKc transgenic linese0
- Treatment
- External feeding of pyruvatee0
- Outcome
- AOX pathwaye0
- Direction
- activatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“External feeding of pyruvate to tuber tissue or isolated mitochondria resulted in activation of the AOX pathway, both in the wild type and the PKc transgenic lines”
t0“Potato”
Claim · model-written summary
Pyruvate levels regulate AOX activity in vivo.
- Taxon
- potatoSolanum tuberosumt0
- Compound
- pyruvatee0
- Outcome
- regulation of AOXe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“providing direct evidence for the regulation of AOX by changes in pyruvate levels”
t0“Potato”
The same questions in other papers
transgenic · quality: sugar starch · Solanum tuberosum (potato)Positive and negative results
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