Abstract
The PGR5 (PROTON GRADIENT REGULATION 5) gene that is required for PSI cyclic electron transport in Arabidopsis was knocked down in rice (Oryza sativa). In three PGR5 knockdown (KD) lines, the PGR5 protein level was reduced to 5-8% of that in the wild type, resulting in a 50% reduction in PGRL1 (PGR5-LIKE PHOTOSYNTHETIC PHENOTYPE 1) protein levels. In ruptured chloroplasts, ferredoxin-dependent plastoquinone reduction activity was partially impaired; the phenotype was mimicked by addition of antimycin A to wild-type chloroplasts. As occurred in the Arabidopsis pgr5 mutant, non-photochemical quenching of Chl fluorescence (NPQ) induction was impaired in the leaves, but the electron transport rate (ETR) was only mildly affected at high light intensity. The P700(+) level was reduced even at low light intensity, suggesting that the PGR5 function was severely disturbed as in the Arabidopsis pgr5 mutant and that the other alternative routes of electrons could not compensate the stromal redox balance. The amplitude of the light-dark electrochromic shift (ECS) signal (ECSt), which reflects the total size of the proton motive force in steady-state photosynthesis, was reduced by 13-25% at approximately the growth light intensity. The CO(2) fixation rate was only slightly reduced in the PGR5 KD lines. Despite the drastic reduction in NPQ and P700(+) levels, total biomass was only slightly reduced in PGR5 KD lines grown at 370 µmol photons m(-2) s(-1). These results suggest that CO(2) fixation and growth rate are very robust in the face of alterations in the fundamental reactions of photosynthesis under constant light conditions in rice.
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Claims 11
Claim · model-written summary
PGR5 protein fell to 5-8% of wild type in three rice knockdown lines.
- Taxon
- Rice
Oryza sativat0 - Treatment
- PGR5 knockdown (KD) linese0
- Gene
- PGR5e0
- Outcome
- PGR5 protein levele0
- Direction
- reducede0
- Value
- 5-8%e0
- Comparator
- wild typee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In three PGR5 knockdown (KD) lines, the PGR5 protein level was reduced to 5-8% of that in the wild type”
t0“Rice”
Claim · model-written summary
PGRL1 protein levels fell by 50% in PGR5 knockdown rice.
- Taxon
- RiceOryza sativat0
- Treatment
- PGR5 knockdown (KD) linese1
- Gene
- PGRL1e0
- Outcome
- PGRL1 (PGR5-LIKE PHOTOSYNTHETIC PHENOTYPE 1) protein levelse0
- Direction
- reductione0
- Value
- 50%e0
- Comparator
- wild typee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“resulting in a 50% reduction in PGRL1 (PGR5-LIKE PHOTOSYNTHETIC PHENOTYPE 1) protein levels.”
e1“In three PGR5 knockdown (KD) lines, the PGR5 protein level was reduced to 5-8% of that in the wild type”
t0“Rice”
Claim · model-written summary
Ferredoxin-dependent plastoquinone reduction was partially impaired in ruptured chloroplasts.
- Taxon
- RiceOryza sativat0
- Organ / stage
- ruptured chloroplastse0
- Treatment
- PGR5 knockdown (KD) linese1
- Outcome
- ferredoxin-dependent plastoquinone reduction activitye0
- Direction
- partially impairede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In ruptured chloroplasts, ferredoxin-dependent plastoquinone reduction activity was partially impaired”
e1“PGR5 knockdown (KD) lines”
t0“Rice”
Claim · model-written summary
Antimycin A mimicked the impaired chloroplast phenotype in wild-type rice.
- Taxon
- RiceOryza sativat0
- Treatment
- addition of antimycin Ae0
- Outcome
- the phenotypee0
- Direction
- mimickede0
- Comparator
- wild-type chloroplastse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the phenotype was mimicked by addition of antimycin A to wild-type chloroplasts.”
t0“Rice”
Claim · model-written summary
Non-photochemical quenching induction was impaired in rice knockdown leaves.
- Taxon
- RiceOryza sativat0
- Organ / stage
- leavese0
- Treatment
- PGR5 knockdown (KD) linese1
- Outcome
- non-photochemical quenching of Chl fluorescence (NPQ) inductione0
- Direction
- impairede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“non-photochemical quenching of Chl fluorescence (NPQ) induction was impaired in the leaves”
e1“PGR5 knockdown (KD) lines”
t0“Rice”
Claim · model-written summary
Electron transport rate was only mildly affected at high light intensity.
- Taxon
- RiceOryza sativat0
- Treatment
- PGR5 knockdown (KD) linese1
- Outcome
- electron transport rate (ETR)e0
- Qualifier
- high light intensitye0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the electron transport rate (ETR) was only mildly affected at high light intensity.”
e1“PGR5 knockdown (KD) lines”
t0“Rice”
Claim · model-written summary
P700(+) level was reduced even at low light intensity.
- Taxon
- RiceOryza sativat0
- Treatment
- PGR5 knockdown (KD) linese1
- Outcome
- P700(+) levele0
- Direction
- reducede0
- Qualifier
- low light intensitye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The P700(+) level was reduced even at low light intensity”
e1“PGR5 knockdown (KD) lines”
t0“Rice”
Claim · model-written summary
The steady-state proton motive force signal ECSt fell 13-25% near growth light intensity.
- Taxon
- RiceOryza sativat0
- Treatment
- PGR5 knockdown (KD) linese1
- Outcome
- amplitude of the light-dark electrochromic shift (ECS) signal (ECSt)e0
- Direction
- reducede0
- Value
- 13-25%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The amplitude of the light-dark electrochromic shift (ECS) signal (ECSt), which reflects the total size of the proton motive force in steady-state photosynthesis, was reduced by 13-25% at approximately the growth light intensity.”
e1“PGR5 knockdown (KD) lines”
t0“Rice”
Claim · model-written summary
CO(2) fixation rate was only slightly reduced in rice PGR5 knockdown lines.
- Taxon
- RiceOryza sativat0
- Treatment
- PGR5 KD linese0
- Outcome
- CO(2) fixation ratee0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The CO(2) fixation rate was only slightly reduced in the PGR5 KD lines.”
t0“Rice”
Claim · model-written summary
Total biomass was only slightly reduced in PGR5 knockdown lines at 370 µmol photons m(-2) s(-1).
- Taxon
- RiceOryza sativat0
- Treatment
- PGR5 KD linese0
- Outcome
- total biomasse0
- Direction
- reducede0
- Qualifier
- 370 µmol photons m(-2) s(-1)e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“total biomass was only slightly reduced in PGR5 KD lines grown at 370 µmol photons m(-2) s(-1).”
t0“Rice”
Claim · model-written summary
The authors infer that CO(2) fixation and growth remain robust to altered photosynthetic reactions under constant light.
- Taxon
- riceOryza sativae0
- Outcome
- CO(2) fixation and growth ratee0
- Qualifier
- alterations in the fundamental reactions of photosynthesis under constant light conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“These results suggest that CO(2) fixation and growth rate are very robust in the face of alterations in the fundamental reactions of photosynthesis under constant light conditions in rice.”
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See all 71 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.