大气中CO2浓度逐渐升高，减小植物气孔开度，进而影响植物的气体交换和导致植物的高温胁迫。但是保卫细胞中CO2如何传导和调控气体交换的过程和机制尚不清楚。在前期工作中我们鉴定出CA1和CA4在CO2信号传导途径中起关键作用，不仅调控气孔运动，还调控气孔发育(发表于Nature Cell Biology, 2010和EMBO J, 2011)，但是CA1/CA4在CO2信号传导中的具体过程和机制还不清楚。本项目旨在研究CA1/CA4及其互作蛋白在CO2信号传导中的具体分子机制。主要内容包括：1) 研究CA1/CA4 介导的CO2调控气孔运动的细胞来源。2) 研究CA1/CA4介导的CO2信号如何在细胞器传导。3) 重点鉴定CA1/CA4的互作蛋白及其功能。4) 研究CA1/CA4介导的CO2调控气孔发育的分子机制。5) 研究CA1/CA4提高水分利用率的生理基础和它们在抗逆改良的应用途径。

Elevated CO2 is an important signal that mediates stomatal closing. The continuing rise in atmospheric CO2 has been shown to reduce stomatal apertures in many plant species and this in turn will increasingly affect carbon fixation, plant water use efficiency and leaf heat stress in plants on a global scale. However, the mechanisms that mediate early CO2 reception and CO2 signaling and control global carbon fixation and water use efficiency of plants have remained completely unknown. Our previous study showed that carbonic anhydrases CA1 and CA4 play key roles in early stomatal CO2 singaling, not only regualte CO2-induced stomatal movement, but also regulate stomatal development. Futher research showed that carbonic anhydrases catalysis is the main mechanism and HCO3- is the main signal to induce stomatal closing (Hu et al, 2010, Nature Cell Biology; Xue et al, 2011, EMBO J). However, the detailed process and mechanism that how CA1 and CA4 regulate CO2-induced stomatal movement and stomatal development remain obscure. The proposed project here is to investigate CA1 and CA4 -interacting proteins and achieve the molecular mechanisms that mediate CO2 signal tranduction in guard cells via these proteins.Specific research aims are proposed：1)Determine where is the original CO2 signal from? 2) Investigate how CA1 and CA4-mediated CO2 transduce in different cell orannelles. 3) Identification of CA1 and CA4-interacting proteins and their roles in CO2-induced stomatal signaling pathway.4)Investigate CO2-controlled stomatal development mechanisms mediated by CA1 and CA4.5)Investigate the physiological mechanism that CA1 and CA4 improve water use efficiency and their possible applications in genetic agricultural improvement.This project is of major relevance for carbon fixation and water use efficiency of plants in light of the continuing atmospheric CO2 increase and focused on CO2 signaling in plant guard cells.