Abstract
accelerated cell death 2 (acd2) mutants of Arabidopsis have spontaneous spreading cell death lesions and constitutive activation of defenses in the absence of pathogen infection. Lesion formation in acd2 plants can be triggered by the bacterial toxin coronatine through a light-dependent process. Coronatine-triggered and spontaneous lesion spreading in acd2 plants also requires protein translation, indicating that cell death occurs by an active process. We have cloned the ACD2 gene; its predicted product shows significant and extensive similarity to red chlorophyll catabolite reductase, which catalyzes one step in the breakdown of the porphyrin component of chlorophyll [Wüthrich, K. L., Bovet, L., Hunziger, P. E., Donnison, I. S. & Hörtensteiner, S. (2000) Plant J. 21, 189-198]. Consistent with this, ACD2 protein contains a predicted chloroplast transit peptide, is processed in vivo, and purifies with the chloroplast fraction in subcellular fractionation experiments. At some stages of development, ACD2 protein also purifies with the mitochondrial fraction. We hypothesize that cell death in acd2 plants is caused by the accumulation of chlorophyll breakdown products. Such catabolites might be specific triggers for cell death or they might induce cellular damage through their ability to absorb light and emit electrons that generate free radicals. In response to infection by Pseudomonas syringae, transgenic plants expressing excess ACD2 protein show reduced disease symptoms but not reduced growth of bacteria. Thus, breakdown products of chlorophyll may act to amplify the symptoms of disease, including cell death and yellowing. We suggest that economically important plants overexpressing ACD2 might also show increased tolerance to pathogens and might be useful for increasing crop yields.
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Claims 11
Claim · model-written summary
The acd2 mutants develop spreading cell death lesions and constitutive defenses without pathogen infection.
- Taxon
- Arabidopsis
Arabidopsise0 - Material
- acd2e0
- Outcome
- spontaneous spreading cell death lesions and constitutive activation of defensese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“accelerated cell death 2 (acd2) mutants of Arabidopsis have spontaneous spreading cell death lesions and constitutive activation of defenses in the absence of pathogen infection.”
Claim · model-written summary
Coronatine triggers light-dependent lesions in acd2 plants.
- Taxon
- ArabidopsisArabidopsist0
- Material
- acd2e0
- Treatment
- bacterial toxin coronatinee0
- Outcome
- Lesion formatione0
- Qualifier
- light-dependent processe0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Lesion formation in acd2 plants can be triggered by the bacterial toxin coronatine through a light-dependent process.”
t0“Arabidopsis”
Claim · model-written summary
Coronatine-triggered and spontaneous acd2 lesion spread requires protein translation.
- Taxon
- ArabidopsisArabidopsist0
- Material
- acd2e0
- Outcome
- lesion spreadinge0
- Qualifier
- protein translatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Coronatine-triggered and spontaneous lesion spreading in acd2 plants also requires protein translation”
t0“Arabidopsis”
Claim · model-written summary
The cloned ACD2 product has extensive similarity to red chlorophyll catabolite reductase.
- Taxon
- ArabidopsisArabidopsist0
- Gene
- ACD2e0
- Outcome
- similarity to red chlorophyll catabolite reductasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“We have cloned the ACD2 gene; its predicted product shows significant and extensive similarity to red chlorophyll catabolite reductase”
t0“Arabidopsis”
Claim · model-written summary
ACD2 protein has a predicted chloroplast transit peptide and is processed in vivo.
- Taxon
- ArabidopsisArabidopsist0
- Gene
- ACD2 proteine0
- Outcome
- predicted chloroplast transit peptide, is processed in vivoe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ACD2 protein contains a predicted chloroplast transit peptide, is processed in vivo”
t0“Arabidopsis”
Claim · model-written summary
ACD2 protein copurifies with chloroplasts.
- Taxon
- ArabidopsisArabidopsist0
- Gene
- ACD2 proteine0
- Outcome
- purifies with the chloroplast fractione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ACD2 protein contains a predicted chloroplast transit peptide, is processed in vivo, and purifies with the chloroplast fraction in subcellular fractionation experiments.”
t0“Arabidopsis”
Claim · model-written summary
At some developmental stages ACD2 protein copurifies with mitochondria.
- Taxon
- ArabidopsisArabidopsist0
- Gene
- ACD2 proteine0
- Outcome
- purifies with the mitochondrial fractione0
- Qualifier
- At some stages of developmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At some stages of development, ACD2 protein also purifies with the mitochondrial fraction.”
t0“Arabidopsis”
Claim · model-written summary
ACD2 overexpression reduces symptoms after Pseudomonas syringae infection.
- Taxon
- ArabidopsisArabidopsist0
- Treatment
- expressing excess ACD2 proteine0
- Interactor
- Pseudomonas syringae
Pseudomonas syringaee0pathogen - Gene
- ACD2 proteine0
- Outcome
- disease symptomse0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In response to infection by Pseudomonas syringae, transgenic plants expressing excess ACD2 protein show reduced disease symptoms but not reduced growth of bacteria.”
t0“Arabidopsis”
Claim · model-written summary
ACD2 overexpression did not reduce Pseudomonas syringae growth.
- Taxon
- ArabidopsisArabidopsist0
- Treatment
- expressing excess ACD2 proteine0
- Interactor
- Pseudomonas syringaePseudomonas syringaee0pathogen
- Gene
- ACD2 proteine0
- Outcome
- growth of bacteriae0
- Direction
- not reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In response to infection by Pseudomonas syringae, transgenic plants expressing excess ACD2 protein show reduced disease symptoms but not reduced growth of bacteria.”
t0“Arabidopsis”
Claim · model-written summary
The authors suggest chlorophyll breakdown products amplify disease symptoms.
- Taxon
- ArabidopsisArabidopsist0
- Compound
- breakdown products of chlorophylle0
- Outcome
- symptoms of disease, including cell death and yellowinge0
- Direction
- amplifye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Thus, breakdown products of chlorophyll may act to amplify the symptoms of disease, including cell death and yellowing.”
t0“Arabidopsis”
Claim · model-written summary
The authors propose that overexpressing ACD2 may improve pathogen tolerance and crop yields.
- Taxon
- plantsViridiplantaee0
- Gene
- ACD2e0
- Outcome
- increased tolerance to pathogens and might be useful for increasing crop yieldse0
Verbatim
e0“We suggest that economically important plants overexpressing ACD2 might also show increased tolerance to pathogens and might be useful for increasing crop yields.”
The same questions in other papers
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pathogen product · disease · ArabidopsisPositive and negative results
6 papers in the same direction as this paper · 3 in the opposite direction
- positive
- positive
- positive
6 papers more in this group
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.