Mapping Cellular Mechanisms of Auxin Signal Transduction

知识价值。植物激素生长素几乎在植物生物学的各个方面都起着至关重要的作用，从植物胚胎的组织和根、芽系统结构的发育到对环境信号的生长控制。所有这些过程都依赖于植物细胞和组织中生长素的局部积累而形成的生长素梯度。生长素水平的增加会激活不同细胞类型的不同细胞反应，以协调植物的生长。了解这种局部积累是如何实现的，以及哪些机制决定了生长素反应的细胞特异性是本研究项目的目标。最近发现，根细胞中的生长素升高会迅速触发胞质Ca2+水平的增加，这可以通过活细胞成像方法进行可视化。基于这一发现，该项目将开发成像分析，以实时生成单个细胞水平上动态生长素信号传导过程的高分辨率地图。这些图谱可以提供定量的经验数据，描绘生长素运输路线，可用于加强和测试生长素调控植物发育的当前计算模型。该项目进一步旨在开发遗传工具来控制细胞质Ca2+水平，从而以非侵入性，时间和空间控制的方式操纵生长素信号。这将有助于确定Ca2+如何促进生长素信号的细胞特异性。更广泛的影响。该项目将为一名博士后和一名研究生提供现代分子和细胞生物学技术的培训机会。此外，参加宾夕法尼亚州立大学向上发展数学和科学暑期研究体验的高中生将通过一个独立的研究项目为该项目做出贡献。在这个项目中，学生将熟悉荧光显微复制的基础知识，并将产生转基因拟南芥系，这将成为植物科学界的有用工具。

Intellectual merit. The plant hormone auxin plays a vital role in virtually every aspect of plant biology, from the organization of the plant embryo and the development of root and shoot system architecture to the control of growth in response to environmental cues. All of these processes depend on the formation of auxin gradients through local accumulation of auxin in plant cells and tissues. Increased auxin levels then activate different cellular responses in different cell types to coordinate plant growth. To understand how such local accumulation is achieved and which mechanisms determine the cellular specificity of auxin responses is the goal of this research program. It has recently been discovered that auxin elevation in root cells rapidly triggers an increase in cytosolic Ca2+ levels that can be visualized using live cell imaging approaches. Based on this discovery, this project will develop imaging assays to generate high-resolution maps of dynamic auxin signaling processes at the level of individual cells in real time. Such maps can provide quantitative empirical data delineating auxin transport routes, which can be used to strengthen and test current computational models of auxin-regulated plant development. This project further aims to develop genetic tools to control cytoplasmic Ca2+ levels and thereby to manipulate auxin signaling in a non-invasive, temporally and spatially controlled manner. This will help to define how Ca2+ contributes to the cellular specificity of auxin signaling.Broader impacts. The project will provide training opportunities in modern molecular and cell biology techniques for one postdoctoral researcher and one graduate student. In addition, high school students participating in the Upward Bound Math and Science Summer Research Experience at Penn State will contribute to the project through an independent research project. In this project, the students will become acquainted with the basics of fluorescence microcopy and will generate transgenic Arabidopsis lines that will serve as useful tools for the plant scientific community.