Formation of the Stomatal Outer Cuticular Ledge Requires a Guard Cell Wall Proline-Rich Protein
Formation of the Stomatal Outer Cuticular Ledge Requires a Guard Cell Wall Proline-Rich Protein
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DOI：
10.1104/pp.16.01715
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发表时间：
2017-06-01
期刊：
影响因子：
7.4
通讯作者：
Gray, Julie E.
中科院分区：
文献类型：
--
作者：
Hunt, Lee;Amsbury, Samuel;Gray, Julie E.
气孔由一对保卫细胞形成，这些保卫细胞具有增厚的弹性细胞壁，可以承受膨胀压力的大幅增加，而膨胀压力必须打开它们周围的孔。我们对 FOCL1 进行了表征，它是一种保卫细胞表达的分泌蛋白，与富含 Hyp 的细胞壁蛋白具有同源性。 FOCL1-GFP 定位于保卫细胞外角质层，缺乏 FOCL1 的植物产生没有角质层的气孔。相反，大多数气孔完全被角质层的连续融合所覆盖，因此植物的蒸腾水平降低并表现出耐旱性。 focl1 保卫细胞较大，响应关闭信号而减小气孔孔径的能力较差，这表明保卫细胞壁的灵活性受损。 FOCL1 也在侧根首字母中表达，它有助于侧根的出现。我们认为 FOCL1 在气孔和根部的这些高度特化的细胞中起作用，以在高膨压下赋予细胞壁强度和/或促进细胞壁和角质层之间的相互作用。
Stomata are formed by a pair of guard cells which have thickened, elastic cell walls to withstand the large increases in turgor pressure that have to be generated to open the pore that they surround. We have characterized FOCL1, a guard cell-expressed, secreted protein with homology to Hyp-rich cell wall proteins. FOCL1-GFP localizes to the guard cell outer cuticular ledge and plants lacking FOCL1 produce stomata without a cuticular ledge. Instead the majority of stomatal pores are entirely covered over by a continuous fusion of the cuticle, and consequently plants have decreased levels of transpiration and display drought tolerance. The focl1 guard cells are larger and less able to reduce the aperture of their stomatal pore in response to closure signals suggesting that the flexibility of guard cell walls is impaired. FOCL1 is also expressed in lateral root initials where it aids lateral root emergence. We propose that FOCL1 acts in these highly specialized cells of the stomata and root to impart cell wall strength at high turgor and/or to facilitate interactions between the cell wall and the cuticle.