Abstract
Rubisco limits photosynthetic CO(2) fixation because of its low catalytic turnover rate (k(cat)) and competing oxygenase reaction. Previous attempts to improve the catalytic efficiency of Rubisco by genetic engineering have gained little progress. Here we demonstrate that the introduction of the small subunit (RbcS) of high k(cat) Rubisco from the C(4) plant sorghum (Sorghum bicolor) significantly enhances k(cat) of Rubisco in transgenic rice (Oryza sativa). Three independent transgenic lines expressed sorghum RbcS at a high level, accounting for 30%, 44%, and 79% of the total RbcS. Rubisco was likely present as a chimera of sorghum and rice RbcS, and showed 1.32- to 1.50-fold higher k(cat) than in nontransgenic rice. Rubisco from transgenic lines showed a higher K(m) for CO(2) and slightly lower specificity for CO(2) than nontransgenic controls. These results suggest that Rubisco in rice transformed with sorghum RbcS partially acquires the catalytic properties of sorghum Rubisco. Rubisco content in transgenic lines was significantly increased over wild-type levels but Rubisco activation was slightly decreased. The expression of sorghum RbcS did not affect CO(2) assimilation rates under a range of CO(2) partial pressures. The J(max)/V(cmax) ratio was significantly lower in transgenic line compared to the nontransgenic plants. These observations suggest that the capacity of electron transport is not sufficient to support the increased Rubisco capacity in transgenic rice. Although the photosynthetic rate was not enhanced, the strategy presented here opens the way to engineering Rubisco for improvement of photosynthesis and productivity in the future.
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Claims 13
Claim · model-written summary
Sorghum RbcS significantly enhanced Rubisco catalytic turnover in transgenic rice.
- Taxon
- rice (Oryza sativa)
Oryza sativae0 - Treatment
- introduction of the small subunit (RbcS)e0
- Gene
- small subunit (RbcS)e0
- Outcome
- k(cat) of Rubiscoe0
- Direction
- enhancese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the introduction of the small subunit (RbcS) of high k(cat) Rubisco from the C(4) plant sorghum (Sorghum bicolor) significantly enhances k(cat) of Rubisco in transgenic rice (Oryza sativa)”
Claim · model-written summary
Three independent transgenic lines expressed sorghum RbcS at 30%, 44%, and 79% of total RbcS.
- Taxon
- riceOryza sativat0
- Gene
- sorghum RbcSe0
- Outcome
- total RbcSe0
- Value
- 30%, 44%, and 79%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Three independent transgenic lines expressed sorghum RbcS at a high level, accounting for 30%, 44%, and 79% of the total RbcS”
t0“Rice”
Claim · model-written summary
Rubisco was likely a chimera of sorghum and rice RbcS.
- Taxon
- riceOryza sativae0
- Gene
- sorghum and rice RbcSe0
- Outcome
- chimerae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Rubisco was likely present as a chimera of sorghum and rice RbcS”
Claim · model-written summary
Transgenic Rubisco had 1.32- to 1.50-fold higher k(cat) than nontransgenic rice.
- Taxon
- riceOryza sativae0
- Treatment
- sorghum and rice RbcSe0
- Outcome
- k(cat)e0
- Direction
- highere0
- Value
- 1.32- to 1.50-folde0
- Comparator
- nontransgenic ricee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Rubisco was likely present as a chimera of sorghum and rice RbcS, and showed 1.32- to 1.50-fold higher k(cat) than in nontransgenic rice”
Claim · model-written summary
Transgenic Rubisco had higher K(m) for CO(2) than nontransgenic controls.
- Taxon
- RiceOryza sativat0
- Treatment
- transgenic linese0
- Outcome
- K(m) for CO(2)e0
- Direction
- highere0
- Comparator
- nontransgenic controlse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Rubisco from transgenic lines showed a higher K(m) for CO(2) and slightly lower specificity for CO(2) than nontransgenic controls”
t0“Rice”
Claim · model-written summary
Transgenic Rubisco had slightly lower CO(2) specificity than nontransgenic controls.
- Taxon
- RiceOryza sativat0
- Treatment
- transgenic linese0
- Outcome
- specificity for CO(2)e0
- Direction
- lowere0
- Comparator
- nontransgenic controlse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Rubisco from transgenic lines showed a higher K(m) for CO(2) and slightly lower specificity for CO(2) than nontransgenic controls”
t0“Rice”
Claim · model-written summary
Rubisco in rice transformed with sorghum RbcS partly acquired sorghum Rubisco catalytic properties.
- Taxon
- riceOryza sativae0
- Gene
- sorghum RbcSe0
- Outcome
- catalytic properties of sorghum Rubiscoe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Rubisco in rice transformed with sorghum RbcS partially acquires the catalytic properties of sorghum Rubisco”
Claim · model-written summary
Rubisco content increased significantly in transgenic lines over wild type.
- Taxon
- RiceOryza sativat0
- Treatment
- transgenic linese0
- Outcome
- Rubisco contente0
- Direction
- increasede0
- Comparator
- wild-typee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Rubisco content in transgenic lines was significantly increased over wild-type levels”
t0“Rice”
Claim · model-written summary
Rubisco activation decreased slightly in transgenic lines.
- Taxon
- RiceOryza sativat0
- Treatment
- sorghum RbcSe1
- Outcome
- Rubisco activatione0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Rubisco activation was slightly decreased”
t0“Sorghum Small Subunit Increases the Catalytic Turnover Rate of Rubisco in Transgenic Rice”
e1“The expression of sorghum RbcS did not affect CO(2) assimilation rates”
Claim · model-written summary
Sorghum RbcS expression did not affect CO(2) assimilation across CO(2) partial pressures.
- Taxon
- RiceOryza sativat0
- Treatment
- expression of sorghum RbcSe0
- Outcome
- CO(2) assimilation ratese0
- Direction
- did not affecte0
- Qualifier
- under a range of CO(2) partial pressurese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The expression of sorghum RbcS did not affect CO(2) assimilation rates under a range of CO(2) partial pressures”
t0“Rice”
Claim · model-written summary
J(max)/V(cmax) ratio was significantly lower in the transgenic line than in nontransgenic plants.
- Taxon
- RiceOryza sativat0
- Treatment
- transgenic linee0
- Outcome
- J(max)/V(cmax) ratioe0
- Direction
- lowere0
- Comparator
- nontransgenic plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The J(max)/V(cmax) ratio was significantly lower in transgenic line compared to the nontransgenic plants”
t0“Rice”
Claim · model-written summary
The authors inferred electron transport capacity could not support increased Rubisco capacity in transgenic rice.
- Taxon
- riceOryza sativae0
- Outcome
- increased Rubisco capacitye0
- Qualifier
- capacity of electron transport is not sufficiente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the capacity of electron transport is not sufficient to support the increased Rubisco capacity in transgenic rice”
Claim · model-written summary
The authors proposed sorghum RbcS transfer as a future route to improve photosynthesis and productivity.
- Taxon
- RiceOryza sativat0
- Outcome
- engineering Rubisco for improvement of photosynthesis and productivitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the strategy presented here opens the way to engineering Rubisco for improvement of photosynthesis and productivity in the future”
t0“Rice”
The same questions in other papers
transgenic · physiology: photosynthesis · Oryza sativa (rice)Positive and negative results
3 papers in the same direction as this paper · 5 in the opposite direction
- positive
- positive
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See all 9 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.