Abstract
A waxy cuticle that serves as a protective barrier against uncontrolled water loss and environmental damage coats the aerial surfaces of land plants. It is composed of a cutin polymer matrix and waxes. Cuticular waxes are complex mixtures of very-long-chain fatty acids and their derivatives. We report here the molecular cloning and characterization of CER4, a wax biosynthetic gene from Arabidopsis (Arabidopsis thaliana). Arabidopsis cer4 mutants exhibit major decreases in stem primary alcohols and wax esters, and slightly elevated levels of aldehydes, alkanes, secondary alcohols, and ketones. This phenotype suggested that CER4 encoded an alcohol-forming fatty acyl-coenzyme A reductase (FAR). We identified eight FAR-like genes in Arabidopsis that are highly related to an alcohol-forming FAR expressed in seeds of jojoba (Simmondsia chinensis). Molecular characterization of CER4 alleles and genomic complementation revealed that one of these eight genes, At4g33790, encoded the FAR required for cuticular wax production. Expression of CER4 cDNA in yeast (Saccharomyces cerevisiae) resulted in the accumulation of C24:0 and C26:0 primary alcohols. Fully functional green fluorescent protein-tagged CER4 protein was localized to the endoplasmic reticulum in yeast cells by confocal microscopy. Analysis of gene expression by reverse transcription-PCR indicated that CER4 was expressed in leaves, stems, flowers, siliques, and roots. Expression of a beta-glucuronidase reporter gene driven by the CER4 promoter in transgenic plants was detected in epidermal cells of leaves and stems, consistent with a dedicated role for CER4 in cuticular wax biosynthesis. CER4 was also expressed in all cell types in the elongation zone of young roots. These data indicate that CER4 is an alcohol-forming FAR that has specificity for very-long-chain fatty acids and is responsible for the synthesis of primary alcohols in the epidermal cells of aerial tissues and in roots.
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Claims 12
Claim · model-written summary
cer4 mutants had major decreases in stem primary alcohols and wax esters.
- Taxon
- Arabidopsis
Arabidopsise0 - Material
- cer4 mutantse0
- Outcome
- stem primary alcohols and wax esterse0
- Direction
- decreasese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Arabidopsis cer4 mutants exhibit major decreases in stem primary alcohols and wax esters”
Claim · model-written summary
cer4 mutants had slightly elevated aldehydes, alkanes and secondary alcohols.
Not reportedTaxonMaterial
Verbatim
e0“slightly elevated levels of aldehydes, alkanes, secondary alcohols, and ketones.”
Claim · model-written summary
cer4 mutants had slightly elevated ketones.
Not reportedTaxonMaterial
Verbatim
e0“slightly elevated levels of aldehydes, alkanes, secondary alcohols, and ketones.”
Claim · model-written summary
Eight FAR-like genes were identified in Arabidopsis.
- Taxon
- ArabidopsisArabidopsise0
- Outcome
- FAR-like genese0
- Value
- eighte0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“We identified eight FAR-like genes in Arabidopsis”
Claim · model-written summary
At4g33790 encoded the FAR required for cuticular wax production.
Not reportedTaxon
Verbatim
e0“At4g33790, encoded the FAR required for cuticular wax production.”
Claim · model-written summary
CER4 expression in yeast accumulated C24:0 and C26:0 primary alcohols.
- Treatment
- Expression of CER4 cDNA in yeaste0
- Gene
- CER4e0
- Outcome
- C24:0 and C26:0 primary alcoholse0
- Direction
- accumulatione0
Not reportedTaxonComparator
Verbatim
e0“Expression of CER4 cDNA in yeast (Saccharomyces cerevisiae) resulted in the accumulation of C24:0 and C26:0 primary alcohols.”
Claim · model-written summary
CER4 protein localized to the endoplasmic reticulum in yeast.
Not reportedTaxon
Verbatim
e0“Fully functional green fluorescent protein-tagged CER4 protein was localized to the endoplasmic reticulum in yeast cells”
Claim · model-written summary
CER4 was expressed in leaves, stems and flowers.
Not reportedTaxon
Verbatim
e0“CER4 was expressed in leaves, stems, flowers, siliques, and roots.”
Claim · model-written summary
CER4 was expressed in siliques and roots.
Not reportedTaxon
Verbatim
e0“CER4 was expressed in leaves, stems, flowers, siliques, and roots.”
Claim · model-written summary
The CER4 promoter reporter was detected in leaf and stem epidermal cells.
Not reportedTaxon
Verbatim
e0“Expression of a beta-glucuronidase reporter gene driven by the CER4 promoter in transgenic plants was detected in epidermal cells of leaves and stems”
Claim · model-written summary
CER4 was expressed in all cell types of the young root elongation zone.
Not reportedTaxon
Verbatim
e0“CER4 was also expressed in all cell types in the elongation zone of young roots.”
Claim · model-written summary
CER4 is an alcohol-forming FAR specific to very-long-chain fatty acids.
Not reportedTaxon
Verbatim
e0“CER4 is an alcohol-forming FAR that has specificity for very-long-chain fatty acids”
The same questions in other papers
transgenic · molecular: metabolites · ArabidopsisPositive and negative results
23 papers in the same direction as this paper · 21 in the opposite direction
- no effect
- positive
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