Signal Transduction in Arabidopsis Root Gravitropism

拟南芥根向地性中的信号转导

• 批准号: 9513991
• 负责人: Simon Gilroy
• 金额: $ 24.39万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-04-01 至 1999-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9513991&HistoricalAwards=false
• 关键词: Signal; Transduction; Arabidopsis; Root; Gravitropism

Gravity is a fundamental signal that regulates plant growth and form. Despite its importance to plant success, the cellular and molecular events whereby higher plants sense and respond to the gravity signal are essentially unknown. It is thought that in the root gravity is perceived in cap cells and that this signal is converted to asymmetrical growth through a mechanism involving asymmetrical auxin and Ca2+ distribution. Much of the debate can be traced to our relative ignorance of the interacting signaling systems that tranduce, coordinate and integrate these tropic responses. The goal of this research is therefore to define these critical gravetropic signaling systems and how they interact, to the cellular level, using the roots of Arabidopsis thaliana as a model system. Experiments are proposed using laser ablation to define the graviperceptive cells of the root cap with single cell resolution. Fluorescence tagging of single cell walls will then be used to map the temporal and spatial components of individual cellular growth response in the elongating region of the root. Confocal and ratio fluorescent imaging will be applied to the intact root to visualize Ca2+- and pH-dependent signaling responses as the root responds to gravity. Signal related changes in these second messengers will then be mimicked or blocked by microinjecting the defined perceptive and responsive cells with Ca2+ and pH-related signaling molecules and their antagonists. Finally, experiments will be performed to generate defined gradients of auxin, Ca2+ and pH in root tissue in intact plants using localized release of caged forms of these putative regulators. These experiments will directly test the hypothesis that asymmetries in these regulators are involved in coordinating the tropic growth along the intact root. Results from the research will extend our understanding of gravity responses in roots specifically, and help define the interactions that integrate the growth responses of plant organs to environmental signals in general.

重力是调节植物生长和形式的基本信号。尽管对植物成功的重要性，但细胞和分子事件具有较高的植物感知并响应重力信号的事件本质上是未知的。 人们认为，在根部重力细胞中，在根部重力中，该信号通过涉及不对称生长素和Ca2+分布的机制转化为不对称生长。 大部分辩论可以追溯到我们对交互，协调和整合这些热带反应的相互作用信号系统的相对无知。 因此，这项研究的目的是使用拟南芥的根作为模型系统来定义这些关键的重型信号系统及其相互作用，以及它们如何相互作用到细胞水平。 提出了使用激光消融的实验，以通过单细胞分辨率定义根盖的颗粒感受器。 然后，将使用单细胞壁的荧光标记来绘制根部伸长区域中单个细胞生长反应的时间和空间成分。 当根对重力响应时，共聚焦和比率荧光成像将应用于完整的根部，以可视化Ca2+ - pH依赖性信号响应。 然后，通过与Ca2+和pH相关的信号分子及其拮抗剂微注射定义的感知和响应性细胞，将模仿或阻断这些第二个使者的信号相关变化。 最后，将进行实验，以在完整植物中使用这些推定的调节剂的笼式形式的局部释放在完整植物中生长生长素，Ca2+和pH的定义梯度。 这些实验将直接检验以下假设：这些调节剂中的不对称性参与沿完整根的热带生长。 研究的结果将扩展我们对根部重力反应的理解，并有助于定义将植物器官与整个环境信号的增长响应整合在一起的相互作用。