title: Stomatal density is controlled by a mesophyll-derived signaling molecule.
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.
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya, Japan.
authors.forename: Tatsuhiko
authors.initials: T
authors.lastname: Kondo
authors.forename: Ryoko
authors.initials: R
authors.lastname: Kajita
authors.forename: Aya
authors.initials: A
authors.lastname: Miyazaki
authors.forename: Mayumi
authors.initials: M
authors.lastname: Hokoyama
authors.forename: Touko
authors.initials: T
authors.lastname: Nakamura-Miura
authors.forename: Satoko
authors.initials: S
authors.lastname: Mizuno
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Masuda
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Irie
authors.forename: Yuki
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Shinobu
authors.initials: S
authors.lastname: Takada
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Kakimoto
authors.forename: Youji
authors.initials: Y
authors.lastname: Sakagami
mesh_terms: D000595:Amino Acid Sequence / Q000502:physiology; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000502:physiology; D008969:Molecular Sequence Data; D010455:Peptides / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D019441:Plant Epidermis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D054046:Plant Stomata / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; C547253:EPF1 protein, Arabidopsis; C542689:EPF2 protein, Arabidopsis; D010455:Peptides; C547254:Stomagen protein, Arabidopsis; D014157:Transcription Factors