Signal Transduction in Root Gravitropism

根向地性中的信号转导

• 批准号: 0212099
• 负责人: Simon Gilroy
• 金额: $ 35万
• 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: 2002
• 资助国家: 美国
• 起止时间: 2002-09-01 至 2006-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0212099&HistoricalAwards=false
• 关键词: Signal; Transduction; Root; Gravitropism

MCB0212099 PI: Gilroy, SimonPROJECT ABSTRACTGravity 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 this most pervasive and constant of environmental signals are essentially unknown. In the root, gravity is perceived in the columella cells of the root cap and this signal is converted to oriented growth in the elongation zone through a mechanism likely involving asymmetrical auxin redistribution. The goal of this research project is to define the cell and molecular nature of the initial gravity-related signaling events generated in the columella cells, using the roots of Arabidopsis thaliana as a model system. Previous research has identified changes in cytoplasmic and cell wall pH as important initial events in gravity signaling in the root cap columella cells. In addition, recent evidence suggests highly localized changes in Ca2+, likely close to membrane surfaces, also accompany some of the earliest events of gravity perception in these cells. Research will therefore concentrate on characterizing how these gravity-related H+ and Ca2+ fluxes are generated and how they are modulated by putative components of the gravity signal transduction system such as the actomyosin cytoskeleton. In addition, transgenic Ca2+ sensors based on the Cameleon green fluorescent protein Ca2+ sensor will be constructed and targeted to the vacuolar, endoplasmic reticulum and plasma membranes. These novel sensors will be used to assess whether membrane-associated Ca2+ microdomains are indeed associated with gravity signaling. The final goal of the research program is to develop single cell mRNA profiling for the columella cells in order to catalog gene expression patterns within the different regions of the root cap. Initial analysis will be targeted at profiling the actin and myosin gene families as these represent strong candidates for encoding parts of the force transmissive network that generates the biochemical signaling events of gravity perception. Plant growth and form are inextricably linked to the developmental impacts of gravity. Yet, despite its fundamental role in regulating development, the precise mechanism whereby plants sense and respond to gravity remains unknown. Results from this research program will therefore seek to define the molecular machinery of the root that allows it to sense gravitational forces. The project will focus on developing microscope-based imaging approaches to visualize the dynamic changes in the levels of ions that are thought to signal the gravity stimulus to the sensitive cells of the root. An understanding of these signaling events should not only help provide a more complete understanding of how plants sense and respond to their environment, but also holds the potential to uncover strategies to regulate plant development through manipulating the responsiveness of defined components of this plant gravity sensing system.

MCB0212099 PI：Gilroy，SimonPROJECT摘要重力是调节植物生长和形态的基本信号。尽管它的重要性，植物的成功，高等植物的细胞和分子的事件，从而感觉和响应这种最普遍和恒定的环境信号基本上是未知的。在根中，在根冠的柱细胞中感知重力，并且该信号通过可能涉及不对称生长素再分配的机制被转换为伸长区中的定向生长。本研究项目的目标是以拟南芥的根为模型系统，确定在柱细胞中产生的初始重力相关信号事件的细胞和分子性质。先前的研究已经确定细胞质和细胞壁pH值的变化是根冠柱细胞中重力信号传导的重要初始事件。此外，最近的证据表明，高度局部化的变化，可能接近膜表面，也伴随着一些最早的事件，在这些细胞的重力感知。因此，研究将集中在表征这些重力相关的H+和Ca2+通量是如何产生的，以及它们是如何被重力信号转导系统的推定成分如肌动球蛋白细胞骨架调制的。此外，基于Cameleon绿色荧光蛋白Ca 2+传感器的转基因Ca 2+传感器将被构建并靶向液泡、内质网和质膜。这些新型传感器将用于评估膜相关的Ca2+微区是否确实与重力信号相关。该研究计划的最终目标是开发柱细胞的单细胞mRNA谱，以便对根冠不同区域内的基因表达模式进行编目。初步分析的目标是分析肌动蛋白和肌球蛋白基因家族，因为这些基因家族代表了编码力传递网络部分的强有力的候选者，该网络产生重力感知的生化信号事件。 植物的生长和形态与重力对发育的影响密不可分。然而，尽管它在调节发育中起着重要作用，但植物感知和响应重力的确切机制仍然未知。因此，这项研究计划的结果将寻求定义允许其感知重力的根的分子机制。该项目将侧重于开发基于显微镜的成像方法，以可视化离子水平的动态变化，这些离子被认为是向根的敏感细胞发出重力刺激的信号。了解这些信号事件不仅有助于更全面地了解植物如何感知和响应环境，而且还可能揭示通过操纵植物重力感应系统的特定组件的响应来调节植物发育的策略。