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态的基本信号。尽管它对植物的成功很重要，但高等植物感知和响应重力信号的细胞和分子事件基本上是未知的。 据认为，在根中，重力在帽细胞中被感知，并且该信号通过涉及不对称生长素和Ca 2+分布的机制被转换为不对称生长。 大部分的争论可以追溯到我们相对忽视的相互作用的信号系统，转导，协调和整合这些热带反应。 因此，本研究的目标是确定这些关键gravetropic信号系统，以及它们如何相互作用，在细胞水平上，使用拟南芥的根作为模型系统。 实验提出了使用激光烧蚀，以确定与单细胞分辨率的根冠的重力感知细胞。 荧光标记的单细胞壁，然后将被用来映射的时间和空间分量的个别细胞生长反应的伸长区域的根。 共聚焦和比率荧光成像将应用于完整的根可视化Ca2+和pH值依赖的信号传导反应的根响应重力。 然后通过显微注射具有Ca 2+和pH相关信号分子及其拮抗剂的限定的感知和响应细胞来模拟或阻断这些第二信使中的信号相关变化。 最后，将进行实验，以产生生长素，Ca2+和pH值在完整的植物根组织中使用这些推定的调节剂的笼状形式的局部释放定义的梯度。 这些实验将直接检验这一假设，即这些调节剂的不对称性参与协调沿着完整根沿着的向性生长。 这项研究的结果将扩展我们对根系重力反应的理解，并有助于定义将植物器官的生长反应与环境信号相结合的相互作用。