Dissecting the Molecular Pathways that Coordinate Lateral Root Initiation with Environmental Signals

剖析协调侧根起始与环境信号的分子途径

• 批准号: 0131690
• 负责人: Jocelyn Malamy
• 金额: $ 34.16万
• 依托单位: University of Chicago
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-08-01 至 2005-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0131690&HistoricalAwards=false
• 关键词: Dissecting; Molecular; Pathways; Coordinate; Lateral

Plants are completely dependent on the resources that are available in their immediate vicinity. Unfortunately, nutrient availability and distribution are in constant flux in the environment. Plants must be able to sense these changes and respond appropriately. This developmental plasticity can be clearly observed in the plant root system. The root system is a highly branched structure that extracts water and nutrients from the soil. Both the number and placement of lateral roots are dramatically affected by environmental cues. This allows the plant to optimize its root system to its unique habitat, compete effectively for soil resources and survive adverse conditions. Lateral roots are formed from mature pericycle cells in the parent root. We have almost no understanding of how pericycle cells are triggered to re-enter the cell-cycle and re-differentiate to create the lateral root primordium. Similarly, very little is known about how certain pericycle cells are selected to proliferate while their neighbors remain quiescent. Finally, it is unclear how external conditions are sensed and the information integrated into decisions about where and when a new lateral root will be formed. The objective of this proposal is to dissect the mechanisms that regulate the initiation of lateral roots. Our main strategy involves the analysis of a lateral root initiation mutant, lin1, that we have recently isolated in Arabidopsis thaliana. While wild-type Arabidopsis plants drastically repress lateral root initiation under certain environmental conditions, the lin1 mutant maintains a highly branched root system. Furthermore, lin1 shows altered patterns of accumulation of auxin, a hormone known to be critical for lateral root initiation. We will clone the LIN1 gene and characterize the LIN1 pathway using genetic, physiological and genomic approaches. These studies will begin to shed light on one of the fundamental mysteries in plant biology: How are the decisions made that coordinate plant development with environmental cues? They will also impact our understanding of how plants are able to selectively activate cell proliferation and organogenesis during vegetative growth. By focusing on the root system, our work will also provide important insights into plant adaptation to water and nutrient stress and may lead to the development of crops able to survive under adverse conditions.

植物完全取决于附近可用的资源。 不幸的是，养分的可用性和分布在环境中持续不断变化。 植物必须能够感知这些变化并做出适当的反应。 在植物根系中可以清楚地观察到这种发展可塑性。 根系是一种高度分支的结构，可从土壤中提取水和养分。 横向根的数量和位置都受到环境线索的极大影响。 这使工厂能够将其根系优化为独特的栖息地，有效地争夺土壤资源并在不利条件下生存。 侧根是由母根中成熟的周周细胞形成的。 我们几乎不了解如何触发周环细胞以重新进入细胞周期并重新分化以创建侧根原原。 同样，对于如何选择某些周围细胞以增殖而在邻居保持静止的情况下，知之甚少。 最后，目前尚不清楚如何感知外部条件，并将信息集成到有关何时何地形成新的横向根的决策中。 该提议的目的是剖析调节侧根起始的机制。 我们的主要策略涉及对我们最近在拟南芥中分离出的横向根启动突变体Lin1的分析。 野生型拟南芥植物在某些环境条件下极大地抑制了横向根开始，但LIN1突变体保持了高度分支的根系。 此外，LIN1显示出生长素的积累的改变模式，生长素是一种激素，已知对于横向根开始至关重要。 我们将使用遗传，生理和基因组方法克隆LIN1基因，并表征LIN1途径。 这些研究将开始阐明植物生物学的基本奥秘之一：如何使该植物开发与环境提示进行协调？ 它们还将影响我们对植物如何在营养生长过程中如何有选择地激活细胞增殖和器官发生的理解。 通过关注根系，我们的工作还将为植物适应水和养分胁迫提供重要的见解，并可能导致在不利条件下能够生存的农作物的发展。