External-calcium Signal Transduction in Arabidopsis Guard Cells

拟南芥保卫细胞中的外部钙信号转导

• 批准号: 0451072
• 负责人: Zhen-Ming Pei
• 金额: $ 45万
• 依托单位: Duke University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-05-01 至 2008-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0451072&HistoricalAwards=false
• 关键词: External; calcium; Signal; Transduction; Arabidopsis

The perception of environmental signals is crucial for various physiological and developmental processes in plants. It is well established that external signals trigger cytosolic free Ca2+ increases in plant cells. However, the molecular components governing these cytosolic Ca2+ changes are poorly understood. The Arabidopsis extracellular Ca2+ (Ca2+o)-sensing receptor (CAS) may represent the only cell-surface receptor cloned so far that has been shown to convert an external stimulus into cytosolic Ca2+ increases in plants. CAS plays an essential role in Ca2+o-induced closing of stomatal pores, which are formed by pairs of guard cells in leaf surface. The long-term goal of this project is to understand the molecular mechanisms of Ca2+o signal transduction in guard cells. In this project, experiments will be carried out to (1) identify Ca2+-binding sites in the CAS N-terminus by site-directed and deletion mutation; (2) confirm Ca2+o activation of CAS triggering Ca2+ release using heterologous expression systems and initiate a screen for Arabidopsis inositol 1,4,5-trisphosphate (IP3) receptor; and (3) identify the molecular components downstream of CAS through complex purification. This project will not only further understanding of guard cell Ca2+o signaling but also shed light on the Ca2+ machineries governing external-signal perception in plants. The broader impacts of this project will include teaching and training of the next generation of scientists at the postdoctoral, graduate, and undergraduate levels.

环境信号的感知对于植物的各种生理和发育过程至关重要。众所周知，外部信号会触发植物细胞中胞质游离 Ca2+ 的增加。然而，人们对控制这些胞质 Ca2+ 变化的分子成分知之甚少。拟南芥细胞外 Ca2+ (Ca2+o) 感应受体 (CAS) 可能是迄今为止克隆的唯一细胞表面受体，已被证明可以将外部刺激转化为植物中细胞质 Ca2+ 的增加。 CAS 在 Ca2+o 诱导的气孔关闭中发挥着重要作用，气孔是由叶表面的成对保卫细胞形成的。该项目的长期目标是了解保卫细胞中Ca2+o信号转导的分子机制。本项目将进行以下实验：（1）通过定点突变和缺失突变来识别CAS N端的Ca2+结合位点； (2) 使用异源表达系统确认 CAS 的 Ca2+o 激活触发 Ca2+ 释放，并启动拟南芥肌醇 1,4,5-三磷酸 (IP3) 受体的筛选； (3)通过复杂的纯化鉴定CAS下游的分子成分。该项目不仅将进一步了解保卫细胞 Ca2+o 信号传导，还将阐明控制植物外部信号感知的 Ca2+ 机制。该项目的更广泛影响将包括对博士后、研究生和本科生级别的下一代科学家进行教学和培训。