微丝骨架介导气孔运动的信号传导机制及其在提高作物水分利用效率上的应用

Stomata provide the main gate controlling gaseous exchange between plants and the environment. Each stomatal pore is surrounded by a pair of guard cells that are able to perceive intrinsic and extrinsic stimuli and make prompt response by regulating stomatal aperture via a complicated but highly efficient guard cell signaling network. It has been found that dynamic actin reassembly constitutes a hub of the guard cell signaling network, although the signaling components directly coupled to this hub still remain elusive. Our recent work identified an actin-binding protein complex (the ARP2/3 complex) whose function is critical for the stomatal sensitivity to a wide range of stimuli like abscisic acid, calcium, light/darkness transition, etc. Using a mutant (hsr3) of the ARPC2 gene that encodes a core subunit of the ARP2/3 complex, we will explore key signaling components regulated by guard cell actin dynamics via a combination of molecular genetic, cell biological and physiological approaches. It is expected that this innovative work will identify, at least partially, the mechanism underlying actin-mediated stomatal movement and further our understanding of the guard cell signalling network. The ultimate goal of our work is to provide theoretical basis for the genetic engineering of stomatal movement, which will help to increase the water use efficiency (WUE) of crops.

气孔是植物控制自身与周围环境进行气体交换的主要通道。环绕气孔的一对保卫细胞能够感应来自外部环境和植物内部的刺激性信号，并通过复杂而高效的保卫细胞信号传导网络对气孔开度进行快速精确调控。微丝骨架的动态变化是保卫细胞信号传导网络的重要节点，但与其直接关联的上、下游胞内信号元件以及相应的信号传导机制尚未明确。我们最近的工作发现了一种微丝骨架结合蛋白复合物（the ARP2/3 complex），其功能紊乱会导致气孔保卫细胞应激性异常。计划利用该蛋白复合物关键亚基的突变体（hsr3）为主要材料，利用分子遗传学、细胞生物学和生理学的成熟技术手段，探寻通过微丝骨架动态聚合而调控的保卫细胞内信号元件。预期在微丝骨架介导气孔运动的机制上取得创新，对保卫细胞信号传导网络取得深入的认识，并为以遗传工程的手段调控气孔开闭从而提高作物水分利用效率提供科学基础。