Kwak June M, Mäser Pascal, Schroeder Julian I
Arabidopsis Book. 2008;6:e0114. doi: 10.1199/tab.0114. Epub 2008 Nov 26.
Guard cells are located in the leaf epidermis and pairs of guard cells surround and form stomatal pores, which regulate CO(2) influx from the atmosphere into leaves for photosynthetic carbon fixation. Stomatal guard cells also regulate water loss of plants via transpiration to the atmosphere. Signal transduction mechanisms in guard cells integrate a multitude of different stimuli to modulate stomatal apertures. Stomata open in response to light. Stomata close in response to drought stress, elevated CO(2), ozone and low humidity. In response to drought, plants synthesize the hormone abscisic acid (ABA) that triggers closing of stomatal pores. Guard cells have become a highly developed model system for dissecting signal transduction mechanisms in plants and for elucidating how individual signaling mechanisms can interact within a network in a single cell. Many new findings have been made in the last few years. This chapter is an update of an electronic interactive chapter in the previous edition of The Arabidopsis Book (Mäser et al. 2003). Here we focus on mechanisms for which genes and mutations have been characterized, including signaling components for which there is substantial signaling, biochemical and genetic evidence. Ion channels have been shown to represent targets of early signal transduction mechanisms and provide functional signaling and quantitative analysis points to determine where and how mutations affect branches within the guard cell signaling network. Although a substantial number of genes and proteins that function in guard cell signaling have been identified in recent years, there are many more left to be identified and the protein-protein interactions within this network will be an important subject of future research. A fully interactive clickable electronic version of this publication can be accessed at the following web site: http://www-biology.ucsd.edu/labs/schroeder/clickablegc2/. The interactive clickable version includes the following features: Figure 1. Model for the roles of ion channels in ABA signaling.Figure 2. Blue light signaling pathways in guard cells.Figure 3. ABA signaling pathways in guard cells.Figure 1 is linked to explanations that appear upon mouse-over. Figure 2 and Figure 3 are clickable and linked to info boxes, which in turn are linked to TAIR, to relevant abstracts in PubMed, and to updated background explanations from Schroeder et al (2001), used with permission of Annual Reviews of Plant Biology.
保卫细胞位于叶片表皮，成对的保卫细胞围绕并形成气孔，气孔调节大气中二氧化碳流入叶片以进行光合碳固定。气孔保卫细胞还通过蒸腾作用调节植物向大气中的水分散失。保卫细胞中的信号转导机制整合多种不同刺激以调节气孔孔径。气孔对光作出反应而张开。气孔对干旱胁迫、二氧化碳浓度升高、臭氧和低湿度作出反应而关闭。响应干旱时，植物合成激素脱落酸（ABA），ABA触发气孔关闭。保卫细胞已成为用于剖析植物信号转导机制以及阐明单个信号转导机制如何在单个细胞的网络中相互作用的高度发达的模型系统。在过去几年中取得了许多新发现。本章是《拟南芥手册》上一版中一个电子互动章节的更新（Mäser等人，2003年）。在这里，我们关注已鉴定出基因和突变的机制，包括有大量信号转导、生化和遗传证据的信号成分。离子通道已被证明是早期信号转导机制的靶点，并提供功能信号转导和定量分析点，以确定突变在保卫细胞信号网络中的何处以及如何影响分支。尽管近年来已鉴定出大量在保卫细胞信号转导中起作用的基因和蛋白质，但仍有更多有待鉴定，并且该网络内的蛋白质 - 蛋白质相互作用将是未来研究的一个重要课题。本出版物的完全交互式可点击电子版本可在以下网站获取：http://www - biology.ucsd.edu/labs/schroeder/clickablegc2/。交互式可点击版本包括以下特征：图1.离子通道在ABA信号转导中的作用模型。图2.保卫细胞中的蓝光信号通路。图3.保卫细胞中的ABA信号通路。图1链接到鼠标悬停时出现的解释。图2和图3可点击并链接到信息框，这些信息框又链接到TAIR、PubMed中的相关摘要以及Schroeder等人（2001年）更新的背景解释，并经《植物生物学年度评论》许可使用。
