Abstract
Stomata are composed of a pair of guard cells and a pore between them, and their density and positions are regulated by developmental and environmental signals. In a screen in which we overexpressed many genes coding for putative secretory proteins one by one in Arabidopsis, we identified a gene named STOMAGEN, which increases stomatal density when overexpressed. The STOMAGEN gene encodes a small peptide with a putative secretory signal sequence at its N-terminus and is expressed preferentially in mesophyll cells. This peptide belongs to the EPIDERMAL PATTERNING FACTOR (EPF) family of the cysteine-rich peptides superfamily. The mature form was a 45-amino-acid peptide (stomagen) with three intramolecular disulfide bonds. Stomagen treatment at very low concentrations, as low as 10 nM, increased the stomatal density of wild-type Arabidopsis plants. We propose that stomagen is a mesophyll-to-epidermis signaling molecule that positively regulates stomatal density. We also suggest that stomagen increases stomatal density by competing with negative regulators EPF1 and EPF2 for the receptor-like protein TOO MANY MOUTHS.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence / physiology
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Arabidopsis / cytology
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Arabidopsis / genetics
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Arabidopsis / metabolism*
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Arabidopsis Proteins / genetics
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Arabidopsis Proteins / metabolism*
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Arabidopsis Proteins / pharmacology
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Cell Differentiation / drug effects
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Cell Differentiation / genetics
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism
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Gene Expression Regulation, Plant / drug effects
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Gene Expression Regulation, Plant / physiology
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Molecular Sequence Data
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Peptides / genetics
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Peptides / metabolism*
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Peptides / pharmacology
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Plant Epidermis / drug effects
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Plant Epidermis / genetics
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Plant Epidermis / metabolism
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Plant Leaves / drug effects
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Plant Leaves / genetics
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Plant Leaves / metabolism
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Plant Stomata / drug effects
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Plant Stomata / genetics
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Plant Stomata / metabolism*
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Protein Structure, Tertiary / physiology
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Signal Transduction / drug effects
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Signal Transduction / physiology
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Transcription Factors / genetics
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Transcription Factors / metabolism*
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Transcription Factors / pharmacology
Substances
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Arabidopsis Proteins
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DNA-Binding Proteins
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EPF1 protein, Arabidopsis
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EPF2 protein, Arabidopsis
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Peptides
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Stomagen protein, Arabidopsis
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Transcription Factors