Abstract
Abstract Transgenic tobacco (Nicotiana tabacum W38) hemizygous for a single antisense gene directed against Rubisco's small subunit had 35% of the Rubisco content of control leaves (15% when homozygous). CO2 assimilation (at 1000 μmol quanta m−2 s−1 and 350 μbar CO2) by the hemizygous leaves was reduced to 40% of that of the controls without material effect on stomatal conductance, chlorophyll content or other photosynthetic components. Leaf soluble protein was reduced commensurately with the reduction in Rubisco. CO2 assimilation rate in the hemizygous leaves remained limited by Rubisco activity at all, even very high, CO2 concentrations. This led to a simple, hyperbolic response of photosynthesis to intraplastid CO2 concentration from which the in vivo catalytic properties of Rubisco were inferred and compared with those of isolated Rubisco in vitro. Using a similar approach, the content of Rubisco activase was suppressed by incorporating a partial cDNA for activase into the tobacco genome in the antisense orientation with respect to a cauliflower mosaic virus 35S promoter. The progeny of a primary transformant with two anti-activase inserts had from < 1% to 20% of the activase content of control plants. Quite severe suppression of activase, to less than 5% of the amount present in control leaves, was required before effects on photosynthesis and growth became apparent, indicating that one activase tetramer must be able to service, continuously, as many as 200 Rubisco octamers. Plants with lower activase contents could not grow unless the atmosphere was enriched with CO2. Their Rubisco was less carbamylated and they had lower CO2 assimilation rates than the controls. The rate of release of 2′-carboxyarabinitol-1-phosphate from Rubisco after illumination of the antiactivase leaves was also impaired. Older anti-activase plants accumulated increasing amounts of Rubisco in their younger leaves, but were unable to carbamylate it. The photosynthetic rate per carbamylated Rubisco active site in the strongly suppressed anti-activase leaves was only approximately 25% of that seen in control leaves, suggesting that activase may not only promote carbamytation of uncarbamylated Rubisco sites, but also accelerate turnover at carbamylated sites.
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Claims 18
Claim · model-written summary
Hemizygous antisense plants had 35% of the Rubisco content of control leaves.
- Taxon
- Nicotiana tabacum
Nicotiana tabacume1 - Material
- W38e1
- Treatment
- hemizygous for a single antisense gene directed against Rubisco's small subunite1
- Gene
- Rubisco's small subunite1
- Outcome
- Rubisco contente1
- Direction
- lowerinferrede1
- Value
- 35%e1
- Comparator
- control leavese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Transgenic tobacco (Nicotiana tabacum W38) hemizygous for a single antisense gene directed against Rubisco's small subunit had 35% of the Rubisco content of control leaves (15% when homozygous)”
Claim · model-written summary
Homozygous antisense plants had 15% of the Rubisco content of control leaves.
- Taxon
- Nicotiana tabacumNicotiana tabacume1
- Treatment
- antisense gene directed against Rubiscoe1
- Outcome
- Rubisco contente1
- Direction
- lowerinferrede1
- Value
- 15%e1
- Qualifier
- when homozygouse1
- Comparator
- control leavese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Transgenic tobacco (Nicotiana tabacum W38) hemizygous for a single antisense gene directed against Rubisco's small subunit had 35% of the Rubisco content of control leaves (15% when homozygous)”
Claim · model-written summary
CO2 assimilation in hemizygous leaves was reduced to 40% of that of the controls.
- Taxon
- Nicotiana tabacumNicotiana tabacume1
- Treatment
- hemizygous for a single antisense gene directed against Rubisco's small subunite1
- Outcome
- CO2 assimilatione2
- Direction
- reducede2
- Value
- 40%e2
- Qualifier
- at 1000 μmol quanta m−2 s−1 and 350 μbar CO2e2
- Comparator
- the controlse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Transgenic tobacco (Nicotiana tabacum W38) hemizygous for a single antisense gene directed against Rubisco's small subunit had 35% of the Rubisco content of control leaves (15% when homozygous)”
e2“CO2 assimilation (at 1000 μmol quanta m−2 s−1 and 350 μbar CO2) by the hemizygous leaves was reduced to 40% of that of the controls”
Claim · model-written summary
Stomatal conductance and chlorophyll content were not materially affected in hemizygous leaves.
- Taxon
- Nicotiana tabacumNicotiana tabacume1
- Treatment
- hemizygous for a single antisense gene directed against Rubisco's small subunite1
- Outcome
- stomatal conductance, chlorophyll contente3
- Direction
- no_changeinferrede3
- Comparator
- the controlse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Transgenic tobacco (Nicotiana tabacum W38) hemizygous for a single antisense gene directed against Rubisco's small subunit had 35% of the Rubisco content of control leaves (15% when homozygous)”
e2“CO2 assimilation (at 1000 μmol quanta m−2 s−1 and 350 μbar CO2) by the hemizygous leaves was reduced to 40% of that of the controls”
e3“without material effect on stomatal conductance, chlorophyll content or other photosynthetic components”
Claim · model-written summary
Leaf soluble protein was reduced in step with the reduction in Rubisco in hemizygous leaves.
- Taxon
- Nicotiana tabacumNicotiana tabacume1
- Treatment
- hemizygous for a single antisense gene directed against Rubisco's small subunite1
- Outcome
- Leaf soluble proteine4
- Direction
- reducede4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Transgenic tobacco (Nicotiana tabacum W38) hemizygous for a single antisense gene directed against Rubisco's small subunit had 35% of the Rubisco content of control leaves (15% when homozygous)”
e4“Leaf soluble protein was reduced commensurately with the reduction in Rubisco”
Claim · model-written summary
CO2 assimilation rate in hemizygous leaves remained limited by Rubisco activity even at very high CO2 concentrations.
- Taxon
- Nicotiana tabacumNicotiana tabacume1
- Outcome
- CO2 assimilation ratee5
- Qualifier
- even very high, CO2 concentrationse5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Transgenic tobacco (Nicotiana tabacum W38) hemizygous for a single antisense gene directed against Rubisco's small subunit had 35% of the Rubisco content of control leaves (15% when homozygous)”
e5“CO2 assimilation rate in the hemizygous leaves remained limited by Rubisco activity at all, even very high, CO2 concentrations”
Claim · model-written summary
Photosynthesis responded hyperbolically to intraplastid CO2 concentration in hemizygous leaves.
- Taxon
- Nicotiana tabacumNicotiana tabacume1
- Outcome
- simple, hyperbolic response of photosynthesis to intraplastid CO2 concentratione6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Transgenic tobacco (Nicotiana tabacum W38) hemizygous for a single antisense gene directed against Rubisco's small subunit had 35% of the Rubisco content of control leaves (15% when homozygous)”
e6“a simple, hyperbolic response of photosynthesis to intraplastid CO2 concentration”
Claim · model-written summary
Progeny with two anti-activase inserts had from less than 1% to 20% of the activase content of control plants.
- Taxon
- Nicotiana tabacumNicotiana tabacume1
- Treatment
- two anti-activase insertse7
- Gene
- activasee7
- Outcome
- activase contente7
- Direction
- lowerinferrede7
- Value
- < 1% to 20%e7
- Comparator
- control plantse7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Transgenic tobacco (Nicotiana tabacum W38) hemizygous for a single antisense gene directed against Rubisco's small subunit had 35% of the Rubisco content of control leaves (15% when homozygous)”
e7“The progeny of a primary transformant with two anti-activase inserts had from < 1% to 20% of the activase content of control plants”
Claim · model-written summary
Effects on photosynthesis and growth became apparent only when activase was suppressed to less than 5% of control leaves.
- Taxon
- Nicotiana tabacumNicotiana tabacume1
- Treatment
- Quite severe suppression of activasee2
- Outcome
- effects on photosynthesis and growth became apparente2
- Value
- less than 5%e2
- Comparator
- control leavese2
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Transgenic tobacco (Nicotiana tabacum W38) hemizygous for a single antisense gene directed against Rubisco's small subunit had 35% of the Rubisco content of control leaves (15% when homozygous)”
e2“Quite severe suppression of activase, to less than 5% of the amount present in control leaves, was required before effects on photosynthesis and growth became apparent”
Claim · model-written summary
One activase tetramer must be able to service as many as 200 Rubisco octamers.
- Taxon
- Nicotiana tabacumNicotiana tabacume1
- Gene
- activasee2
- Outcome
- service, continuously, as many as 200 Rubisco octamerse2
- Value
- 200 Rubisco octamerse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Transgenic tobacco (Nicotiana tabacum W38) hemizygous for a single antisense gene directed against Rubisco's small subunit had 35% of the Rubisco content of control leaves (15% when homozygous)”
e2“indicating that one activase tetramer must be able to service, continuously, as many as 200 Rubisco octamers”
Claim · model-written summary
Plants with lower activase contents could not grow unless the atmosphere was enriched with CO2.
- Taxon
- Nicotiana tabacumNicotiana tabacume1
- Treatment
- lower activase contentse2
- Outcome
- could not growe2
- Qualifier
- unless the atmosphere was enriched with CO2e2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Transgenic tobacco (Nicotiana tabacum W38) hemizygous for a single antisense gene directed against Rubisco's small subunit had 35% of the Rubisco content of control leaves (15% when homozygous)”
e2“Plants with lower activase contents could not grow unless the atmosphere was enriched with CO2”
Claim · model-written summary
Rubisco in plants with lower activase contents was less carbamylated than in controls.
- Taxon
- Nicotiana tabacumNicotiana tabacume1
- Treatment
- lower activase contentse2
- Outcome
- carbamylatede3
- Direction
- lesse3
- Comparator
- the controlse3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Transgenic tobacco (Nicotiana tabacum W38) hemizygous for a single antisense gene directed against Rubisco's small subunit had 35% of the Rubisco content of control leaves (15% when homozygous)”
e2“Plants with lower activase contents could not grow unless the atmosphere was enriched with CO2”
e3“Their Rubisco was less carbamylated and they had lower CO2 assimilation rates than the controls”
Claim · model-written summary
CO2 assimilation rates in plants with lower activase contents were lower than in controls.
- Taxon
- Nicotiana tabacumNicotiana tabacume1
- Treatment
- lower activase contentse2
- Outcome
- CO2 assimilation ratese3
- Direction
- lowere3
- Comparator
- the controlse3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Transgenic tobacco (Nicotiana tabacum W38) hemizygous for a single antisense gene directed against Rubisco's small subunit had 35% of the Rubisco content of control leaves (15% when homozygous)”
e2“Plants with lower activase contents could not grow unless the atmosphere was enriched with CO2”
e3“Their Rubisco was less carbamylated and they had lower CO2 assimilation rates than the controls”
Claim · model-written summary
Release of 2′-carboxyarabinitol-1-phosphate from Rubisco after illumination was impaired in antiactivase leaves.
- Taxon
- Nicotiana tabacumNicotiana tabacume1
- Treatment
- antiactivasee2
- Outcome
- rate of release of 2′-carboxyarabinitol-1-phosphate from Rubiscoe2
- Direction
- impairede2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Transgenic tobacco (Nicotiana tabacum W38) hemizygous for a single antisense gene directed against Rubisco's small subunit had 35% of the Rubisco content of control leaves (15% when homozygous)”
e2“The rate of release of 2′-carboxyarabinitol-1-phosphate from Rubisco after illumination of the antiactivase leaves was also impaired”
Claim · model-written summary
Older anti-activase plants accumulated increasing amounts of Rubisco in their younger leaves.
- Taxon
- Nicotiana tabacumNicotiana tabacume1
- Organ / stage
- younger leavese2
- Treatment
- anti-activasee2
- Outcome
- accumulated increasing amounts of Rubiscoe2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Transgenic tobacco (Nicotiana tabacum W38) hemizygous for a single antisense gene directed against Rubisco's small subunit had 35% of the Rubisco content of control leaves (15% when homozygous)”
e2“Older anti-activase plants accumulated increasing amounts of Rubisco in their younger leaves, but were unable to carbamylate it”
Claim · model-written summary
Older anti-activase plants were unable to carbamylate the Rubisco they accumulated.
- Taxon
- Nicotiana tabacumNicotiana tabacume1
- Treatment
- anti-activasee2
- Outcome
- unable to carbamylatee2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Transgenic tobacco (Nicotiana tabacum W38) hemizygous for a single antisense gene directed against Rubisco's small subunit had 35% of the Rubisco content of control leaves (15% when homozygous)”
e2“Older anti-activase plants accumulated increasing amounts of Rubisco in their younger leaves, but were unable to carbamylate it”
Claim · model-written summary
Photosynthetic rate per carbamylated Rubisco active site in strongly suppressed anti-activase leaves was approximately 25% of that in control leaves.
- Taxon
- Nicotiana tabacumNicotiana tabacume1
- Treatment
- strongly suppressed anti-activasee2
- Outcome
- photosynthetic rate per carbamylated Rubisco active sitee2
- Direction
- lowerinferrede2
- Value
- approximately 25%e2
- Comparator
- control leavese2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Transgenic tobacco (Nicotiana tabacum W38) hemizygous for a single antisense gene directed against Rubisco's small subunit had 35% of the Rubisco content of control leaves (15% when homozygous)”
e2“The photosynthetic rate per carbamylated Rubisco active site in the strongly suppressed anti-activase leaves was only approximately 25% of that seen in control leaves”
Claim · model-written summary
Activase may promote carbamylation of uncarbamylated Rubisco sites and accelerate turnover at carbamylated sites.
- Taxon
- Nicotiana tabacumNicotiana tabacume1
- Gene
- activasee2
- Outcome
- turnover at carbamylated sitese2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Transgenic tobacco (Nicotiana tabacum W38) hemizygous for a single antisense gene directed against Rubisco's small subunit had 35% of the Rubisco content of control leaves (15% when homozygous)”
e2“suggesting that activase may not only promote carbamytation of uncarbamylated Rubisco sites, but also accelerate turnover at carbamylated sites”
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See all 10 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.