Abstract
UDP-glucose, the precursor for cellulose biosynthesis, can be produced via the catalysis of sucrose by sucrose synthase (SuSy) or through the phosphorylation of glucose-I-phosphate by UDP-glucose pyrophosphorylase (UGPase). As such, these genes, together with sucrose phosphate synthase (SPS) which recycles fructose (an inhibitor of SuSy), are interesting targets for altering carbon allocation in plants. In an attempt to alter cell wall biosynthesis in plants, targeted overexpression of SuSy, UGPase and SPS independently and in a pyramiding strategy was assessed in tobacco. All lines displayed enhanced growth and biomass production, and in the case of double and triple transgenics, there was an additive effect. Despite the increased growth rates, there was no consistent change in soluble carbohydrate pools. Furthermore, only the triple transgenics had constant changes in structural carbohydrates: with increased hemicellulose content and slight increases in cellulose. Collectively, these results support the role of SPS, SuSy and UGPase in maintaining sink strength, but suggest that the reallocation of carbon to cellulose production in tobacco may not be possible by overexpressing these genes. In contrast, transgenic poplar overexpressing UGPase produced significantly more cellulose than wild-type trees. However, this was accompanied by a severe reduction in growth and the production of a salicylic acid glucoside (SAG) in significant quantities. The UDP-glucose generated by UGPase overexpression appeared to participate in both the synthesis of cellulose and SAG, suggesting that cellulose biosynthesis may be limited by the cellulose synthase complex. Poplar transformed with SuSy and with SuSy x UGPase also had increased cellulose production. The trees were phenotypically normal, with only minor reductions in height growth in some lines. It appears that UDP-glucose may be channelled directly to the cellulose synthase complex by SuSy. The increased cellulose content was associated with an increase in cell wall crystallinity, but there was no change in microfibril angle, confirming the re-allocation to cellulose synthesis was not the result of tension wood formation, again supporting the hypothesis that the cellulose synthase complex is the limiting factor. Clearly, it is possible to alter cellulose deposition in trees by augmenting sucrose metabolism to produce UDP-glucose, the precursor to cellulose biosynthesis.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 20
Claim · model-written summary
Overexpression of SuSy, UGPase and SPS in tobacco, independently and in combination, enhanced growth and biomass production in all lines.
- Taxon
- tobacco
Nicotiana tabacume0 - Treatment
- targeted overexpression of SuSy, UGPase and SPSe0
- Gene
- SuSy, UGPase and SPSe0
- Outcome
- growth and biomass productione1
- Direction
- enhancede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“targeted overexpression of SuSy, UGPase and SPS independently and in a pyramiding strategy was assessed in tobacco”
e1“All lines displayed enhanced growth and biomass production”
Claim · model-written summary
In double and triple transgenic tobacco lines the growth enhancement was additive.
- Taxon
- tobaccoNicotiana tabacume0
- Treatment
- double and triple transgenicse1
- Outcome
- additive effecte1
- Direction
- increaseinferrede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tobacco”
e1“in the case of double and triple transgenics, there was an additive effect”
Claim · model-written summary
Despite increased growth rates, tobacco overexpression lines showed no consistent change in soluble carbohydrate pools.
- Taxon
- tobaccoNicotiana tabacume0
- Outcome
- soluble carbohydrate poolse1
- Direction
- no_changeinferrede1
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tobacco”
e1“there was no consistent change in soluble carbohydrate pools”
Claim · model-written summary
Only the triple transgenic tobacco lines had constant changes in structural carbohydrates, with increased hemicellulose content.
- Taxon
- tobaccoNicotiana tabacume0
- Treatment
- triple transgenicse1
- Outcome
- hemicellulose contente1
- Direction
- increasede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tobacco”
e1“only the triple transgenics had constant changes in structural carbohydrates: with increased hemicellulose content and slight increases in cellulose”
Claim · model-written summary
Only the triple transgenic tobacco lines showed slight increases in cellulose.
- Taxon
- tobaccoNicotiana tabacume0
- Treatment
- triple transgenicse1
- Outcome
- cellulosee1
- Direction
- slight increasese1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tobacco”
e1“only the triple transgenics had constant changes in structural carbohydrates: with increased hemicellulose content and slight increases in cellulose”
Claim · model-written summary
Transgenic poplar overexpressing UGPase produced significantly more cellulose than wild-type trees.
- Treatment
- overexpressing UGPasee0
- Gene
- UGPasee0
- Outcome
- cellulosee0
- Direction
- moree0
- Comparator
- wild-type treese0
PopulusOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transgenic poplar overexpressing UGPase produced significantly more cellulose than wild-type trees”
Claim · model-written summary
UGPase-overexpressing poplar showed a severe reduction in growth.
- Treatment
- overexpressing UGPasee0
- Gene
- UGPasee0
- Outcome
- growthe1
- Direction
- reductione1
- Comparator
- wild-type treese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transgenic poplar overexpressing UGPase produced significantly more cellulose than wild-type trees”
e1“a severe reduction in growth”
Claim · model-written summary
UGPase-overexpressing poplar produced a salicylic acid glucoside (SAG) in significant quantities.
- Treatment
- overexpressing UGPasee0
- Gene
- UGPasee0
- Outcome
- production of a salicylic acid glucoside (SAG)e1
- Direction
- increaseinferrede1
- Comparator
- wild-type treese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transgenic poplar overexpressing UGPase produced significantly more cellulose than wild-type trees”
e1“the production of a salicylic acid glucoside (SAG) in significant quantities”
Claim · model-written summary
The UDP-glucose generated by UGPase overexpression appeared to participate in both cellulose and SAG synthesis in poplar.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“hybrid poplar”
e1“The UDP-glucose generated by UGPase overexpression appeared to participate in both the synthesis of cellulose and SAG”
Claim · model-written summary
Authors suggest that cellulose biosynthesis in poplar may be limited by the cellulose synthase complex.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“hybrid poplar”
e1“cellulose biosynthesis may be limited by the cellulose synthase complex”
Claim · model-written summary
Poplar transformed with SuSy had increased cellulose production.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Poplar transformed with SuSy and with SuSy x UGPase also had increased cellulose production”
Claim · model-written summary
Poplar transformed with SuSy x UGPase had increased cellulose production.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Poplar transformed with SuSy and with SuSy x UGPase also had increased cellulose production”
Claim · model-written summary
The SuSy and SuSy x UGPase poplar trees were phenotypically normal.
Verbatim
e0“The trees were phenotypically normal”
Claim · model-written summary
The trees showed only minor reductions in height growth in some lines.
Not reportedTaxon
Verbatim
e0“only minor reductions in height growth in some lines”
Claim · model-written summary
Authors suggest UDP-glucose may be channelled directly to the cellulose synthase complex by SuSy in poplar.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“hybrid poplar”
e1“UDP-glucose may be channelled directly to the cellulose synthase complex by SuSy”
Claim · model-written summary
In poplar, the increased cellulose content was associated with an increase in cell wall crystallinity.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“hybrid poplar”
e1“The increased cellulose content was associated with an increase in cell wall crystallinity”
Claim · model-written summary
In poplar there was no change in microfibril angle with the increased cellulose content.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“hybrid poplar”
e1“there was no change in microfibril angle”
Claim · model-written summary
Authors conclude the re-allocation to cellulose synthesis in poplar was not the result of tension wood formation.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“hybrid poplar”
e1“the re-allocation to cellulose synthesis was not the result of tension wood formation”
Claim · model-written summary
Authors conclude cellulose deposition in trees can be altered by augmenting sucrose metabolism to produce UDP-glucose.
Verbatim
e0“it is possible to alter cellulose deposition in trees by augmenting sucrose metabolism to produce UDP-glucose”
Claim · model-written summary
The tobacco results support a role of SPS, SuSy and UGPase in maintaining sink strength.
- Taxon
- tobaccoNicotiana tabacume0
- Gene
- SPS, SuSy and UGPasee1
- Outcome
- maintaining sink strengthe1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tobacco”
e1“these results support the role of SPS, SuSy and UGPase in maintaining sink strength”
The same questions in other papers
transgenic · yield · Populus (poplar)Results agree
1 paper in the same direction as this paper
- positive
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.