Stomatal density is controlled by a mesophyll-derived signaling molecule.
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.
Kondo
Tatsuhiko
T
Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya, Japan.
Kajita
Ryoko
R
Miyazaki
Aya
A
Hokoyama
Mayumi
M
Nakamura-Miura
Touko
T
Mizuno
Satoko
S
Masuda
Yuichi
Y
Irie
Kazuhiro
K
Tanaka
Yuki
Y
Takada
Shinobu
S
Kakimoto
Tatsuo
T
Sakagami
Youji
Y
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
D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; C547253:EPF1 protein, Arabidopsis; C542689:EPF2 protein, Arabidopsis; D010455:Peptides; C547254:Stomagen protein, Arabidopsis; D014157:Transcription Factors