Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya, Japan.
Plant Cell Physiol. 2010 Jan;51(1):1-8. doi: 10.1093/pcp/pcp180. Epub 2009 Dec 9.
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.
气孔由一对保卫细胞和它们之间的孔隙组成，其密度和位置受发育和环境信号的调节。在我们逐个过表达拟南芥中许多编码假定分泌蛋白的基因的筛选中，我们鉴定了一个名为 STOMAGEN 的基因，该基因过表达时会增加气孔密度。STOMAGEN 基因编码一种小肽，其 N 端具有假定的分泌信号序列，在叶肉细胞中优先表达。该肽属于富含半胱氨酸的肽超家族中的表皮模式因子 (EPF) 家族。成熟形式为具有三个分子内二硫键的 45 个氨基酸肽（stomagen）。以非常低的浓度（低至 10 nM）施用 stomagen 可增加野生型拟南芥植物的气孔密度。我们提出 stomagen 是一种叶肉到表皮的信号分子，可正向调节气孔密度。我们还假设 stomagen 通过与负调节因子 EPF1 和 EPF2 竞争受体样蛋白 TOO MANY MOUTHS 来增加气孔密度。
