气孔运动中的活性氧信号

大量研究证明活性氧(ROS)在气孔运动中起信号分子的作用。保卫细胞中ROS的产生依赖于特定的酶,其中NADPH氧化酶组分RBOH已得到深入研究,并已证实其参与生物与非生物胁迫反应。植物激素包括脱落酸(ABA)、水杨酸(SA)、乙烯、生长素及细胞分裂素等,它们均通过ROS的介导来调控气孔运动。生物胁迫(如毒性细菌和真菌)也会调控气孔运动。ROS参与这些调控过程。保卫细胞中存在多层次对ROS产生及其作用的调节,抗氧化活性物质和ROS敏感蛋白(如蛋白激酶和磷酸酶)均可传递ROS信号并调节气孔运动。ROS对离子通道调节的证据也越来越多。保卫细胞由于可通过ROS整合复杂的信号途径,已成为研究植物ROS信号转导过程的良好模式系统。

Reactive Oxygen Species Signaling in Stomata

Reactive oxygen species （ROS） act as signaling molecules in stomata guard cells. ROS generation occurs in guard cells via specific enzymes. The most-studied enzymatic source is the NADPH oxidase component RBOH, which is involved in both abiotic and biotic stresses. Hormones, such as abscisic acid, salicylic acid, ethylene, auxin, and cytokinin, affect ROS-mediated responses in stomata. Biotic stresses, such as virulent bacteria and fungi, also affect stomata movements, where ROS likely play a role. Regulation of ROS production and action occurs at various levels, including antioxidant activities as well as ROS-sensitive proteins, such as kinases and phosphatases, which transduce ROS to affect stomatal closure. Evidence is gradually emerging of the ROS regulation of ion channels in stomata. Guard cells are an attractive model to study ROS signal transduction because of a complex integration of signaling pathways mediated via ROS.