Abstract
BACKGROUND: The Arabidopsis var2 mutant displays a unique green and white/yellow leaf variegation phenotype and lacks VAR2, a chloroplast FtsH metalloprotease. We are characterizing second-site var2 genetic suppressors as means to better understand VAR2 function and to study the regulation of chloroplast biogenesis. RESULTS: In this report, we show that the suppression of var2 variegation in suppressor line TAG-11 is due to the disruption of the SUPPRESSOR OF VARIEGATION3 (SVR3) gene, encoding a putative TypA-like translation elongation factor. SVR3 is targeted to the chloroplast and svr3 single mutants have uniformly pale green leaves at 22°C. Consistent with this phenotype, most chloroplast proteins and rRNA species in svr3 have close to normal accumulation profiles, with the notable exception of the Photosystem II reaction center D1 protein, which is present at greatly reduced levels. When svr3 is challenged with chilling temperature (8°C), it develops a pronounced chlorosis that is accompanied by abnormal chloroplast rRNA processing and chloroplast protein accumulation. Double mutant analysis indicates a possible synergistic interaction between svr3 and svr7, which is defective in a chloroplast pentatricopeptide repeat (PPR) protein. CONCLUSIONS: Our findings, on one hand, reinforce the strong genetic link between VAR2 and chloroplast translation, and on the other hand, point to a critical role of SVR3, and possibly some aspects of chloroplast translation, in the response of plants to chilling stress.
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Claims 12
Claim · model-written summary
TAG-11 suppression of var2 variegation resulted from disruption of SVR3.
- Taxon
- Arabidopsis
Arabidopsise0 - Material
- TAG-11e1
- Gene
- SUPPRESSOR OF VARIEGATION3 (SVR3)e1
- Outcome
- suppression of var2 variegatione1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The Arabidopsis var2 mutant”
e1“the suppression of var2 variegation in suppressor line TAG-11 is due to the disruption of the SUPPRESSOR OF VARIEGATION3 (SVR3) gene”
Claim · model-written summary
SVR3 encodes a putative TypA-like translation elongation factor.
- Taxon
- ArabidopsisArabidopsise0
- Gene
- SUPPRESSOR OF VARIEGATION3 (SVR3)e1
- Outcome
- putative TypA-like translation elongation factore1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The Arabidopsis var2 mutant”
e1“SUPPRESSOR OF VARIEGATION3 (SVR3) gene, encoding a putative TypA-like translation elongation factor.”
Claim · model-written summary
SVR3 protein is targeted to the chloroplast.
- Taxon
- ArabidopsisArabidopsise0
- Gene
- SVR3e1
- Outcome
- targeted to the chloroplaste1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The Arabidopsis var2 mutant”
e1“SVR3 is targeted to the chloroplast”
Claim · model-written summary
svr3 single mutants had uniformly pale green leaves at 22°C.
- Taxon
- ArabidopsisArabidopsise0
- Material
- svr3 single mutantse1
- Organ / stage
- leavese1
- Outcome
- uniformly pale green leavese1
- Qualifier
- 22°Ce1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The Arabidopsis var2 mutant”
e1“svr3 single mutants have uniformly pale green leaves at 22°C.”
Claim · model-written summary
Most chloroplast proteins and rRNAs in svr3 accumulated near normal levels.
- Taxon
- ArabidopsisArabidopsise0
- Material
- svr3e1
- Outcome
- chloroplast proteins and rRNA speciese1
- Direction
- close to normale1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The Arabidopsis var2 mutant”
e1“most chloroplast proteins and rRNA species in svr3 have close to normal accumulation profiles”
Claim · model-written summary
Photosystem II D1 protein was greatly reduced in svr3.
- Taxon
- ArabidopsisArabidopsise0
- Gene
- Photosystem II reaction center D1 proteine1
- Outcome
- Photosystem II reaction center D1 proteine1
- Direction
- greatly reducede1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The Arabidopsis var2 mutant”
e1“Photosystem II reaction center D1 protein, which is present at greatly reduced levels.”
Claim · model-written summary
Chilling at 8°C caused pronounced chlorosis in svr3.
- Taxon
- ArabidopsisArabidopsise0
- Material
- svr3e1
- Treatment
- chilling temperature (8°C)e1
- Outcome
- pronounced chlorosise1
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The Arabidopsis var2 mutant”
e1“When svr3 is challenged with chilling temperature (8°C), it develops a pronounced chlorosis”
Claim · model-written summary
Chilled svr3 showed abnormal chloroplast rRNA processing.
- Taxon
- ArabidopsisArabidopsise0
- Material
- svr3e1
- Treatment
- chilling temperature (8°C)e1
- Outcome
- abnormal chloroplast rRNA processinge1
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The Arabidopsis var2 mutant”
e1“When svr3 is challenged with chilling temperature (8°C), it develops a pronounced chlorosis that is accompanied by abnormal chloroplast rRNA processing”
Claim · model-written summary
Chilled svr3 showed abnormal chloroplast protein accumulation.
- Taxon
- ArabidopsisArabidopsise0
- Material
- SVR3e2
- Treatment
- chilling temperature (8°C)e1
- Outcome
- chloroplast protein accumulatione1
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The Arabidopsis var2 mutant”
e1“chilling temperature (8°C), it develops a pronounced chlorosis that is accompanied by abnormal chloroplast rRNA processing and chloroplast protein accumulation.”
e2“the suppression of var2 variegation in suppressor line TAG-11 is due to the disruption of the SUPPRESSOR OF VARIEGATION3 (SVR3) gene”
Claim · model-written summary
Double-mutant analysis suggested possible synergy between svr3 and svr7.
- Taxon
- ArabidopsisArabidopsise0
- Gene
- svr3 and svr7e1
- Outcome
- possible synergistic interactione1
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The Arabidopsis var2 mutant”
e1“Double mutant analysis indicates a possible synergistic interaction between svr3 and svr7”
Claim · model-written summary
Findings support a strong genetic link between VAR2 and chloroplast translation.
- Taxon
- ArabidopsisArabidopsise0
- Gene
- VAR2e1
- Outcome
- strong genetic linke1
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The Arabidopsis var2 mutant”
e1“reinforce the strong genetic link between VAR2 and chloroplast translation”
Claim · model-written summary
Authors inferred a critical SVR3 role in plant chilling response.
- Taxon
- ArabidopsisArabidopsise0
- Gene
- SVR3e1
- Outcome
- response of plants to chilling stresse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The Arabidopsis var2 mutant”
e1“point to a critical role of SVR3, and possibly some aspects of chloroplast translation, in the response of plants to chilling stress.”
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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.