Abstract
Constitutive expression of the Escherichia coli ppa gene encoding inorganic pyrophosphatase resulted in sugar accumulation in source leaves and stunted growth of transgenic tobacco plants. The reason for this phenotype was hypothesized to be reduced sucrose utilization and loading into the phloem. To study the role of PPi in phloem cells, a chimeric gene was constructed using the phloem-specific rolC promoter of Agrobacterium rhizogenes to drive the expression of the ppa gene. Removal of cytosolic PPi in those cells resulted in photoassimilate accumulation in source leaves, chlorophyll loss, and reduced plant growth. From these data, it was postulated that sucrose hydrolysis via sucrose synthase is essential for assimilate partitioning. To bypass the PPi-dependent sucrose synthase step, transgenic plants were produced that express various levels of the yeast suc2 gene, which encodes cytosolic invertase, in their phloem cells. To combine the phloem-specific expression of the ppa gene and the suc2 gene, crosses between invertase- and pyrophosphatase-containing transgenic plants were performed. Analysis of their offspring revealed that invertase can complement the phenotypic effects caused by the removal of PPi in phloem cells.
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Claims 6
Claim · model-written summary
Constitutive ppa expression caused sugar accumulation in source leaves.
- Taxon
- tobacco plants
Nicotiana tabacume0 - Treatment
- Constitutive expression of the Escherichia coli ppa genee0
- Gene
- Escherichia coli ppa genee0
- Outcome
- sugar accumulation in source leavese0
- Direction
- accumulatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Constitutive expression of the Escherichia coli ppa gene encoding inorganic pyrophosphatase resulted in sugar accumulation in source leaves and stunted growth of transgenic tobacco plants.”
Claim · model-written summary
Constitutive ppa expression stunted transgenic tobacco growth.
- Taxon
- tobacco plantsNicotiana tabacume0
- Treatment
- Constitutive expression of the Escherichia coli ppa genee0
- Gene
- Escherichia coli ppa genee0
- Outcome
- stunted growthe0
- Direction
- stuntede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Constitutive expression of the Escherichia coli ppa gene encoding inorganic pyrophosphatase resulted in sugar accumulation in source leaves and stunted growth of transgenic tobacco plants.”
Claim · model-written summary
Removing cytosolic PPi in phloem cells accumulated photoassimilates in source leaves.
- Taxon
- PlantsViridiplantaet0
- Treatment
- Removal of cytosolic PPie0
- Outcome
- photoassimilate accumulation in source leavese0
- Direction
- accumulatione0
Not reportedComparator
Verbatim
e0“Removal of cytosolic PPi in those cells resulted in photoassimilate accumulation in source leaves, chlorophyll loss, and reduced plant growth.”
t0“Transgenic Plants”
Claim · model-written summary
Removing cytosolic PPi in phloem cells caused chlorophyll loss.
- Taxon
- PlantsViridiplantaet0
- Treatment
- Removal of cytosolic PPie0
- Outcome
- chlorophyll losse0
- Direction
- losse0
Not reportedComparator
Verbatim
e0“Removal of cytosolic PPi in those cells resulted in photoassimilate accumulation in source leaves, chlorophyll loss, and reduced plant growth.”
t0“Transgenic Plants”
Claim · model-written summary
Removing cytosolic PPi in phloem cells reduced plant growth.
- Taxon
- PlantsViridiplantaet0
- Treatment
- Removal of cytosolic PPie0
- Outcome
- reduced plant growthe0
- Direction
- reducede0
Not reportedComparator
Verbatim
e0“Removal of cytosolic PPi in those cells resulted in photoassimilate accumulation in source leaves, chlorophyll loss, and reduced plant growth.”
t0“Transgenic Plants”
Claim · model-written summary
Phloem invertase complemented the phenotypic effects of PPi removal.
- Taxon
- PlantsViridiplantaet0
- Treatment
- invertasee0
- Outcome
- phenotypic effectse0
Not reportedComparatorDirection
Verbatim
e0“Analysis of their offspring revealed that invertase can complement the phenotypic effects caused by the removal of PPi in phloem cells.”
t0“Transgenic Plants”
The same questions in other papers
overexpression · molecular: metabolites · Nicotiana tabacum (tobacco)Positive and negative results
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- positive
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See all 12 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.