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.

植物完全依赖于其附近的可用资源。 不幸的是，养分的可用性和分布在环境中不断变化。 植物必须能够感知这些变化并做出适当的反应。 这种发育可塑性可以在植物根系中清楚地观察到。 根系是高度分枝的结构，从土壤中吸收水分和养分。 侧根的数量和位置都受到环境因素的显着影响。 这使得植物能够根据其独特的栖息地优化根系，有效竞争土壤资源并在不利条件下生存。 侧根由母根中成熟的中柱鞘细胞形成。 我们几乎不了解中柱鞘细胞如何被触发重新进入细胞周期并重新分化以产生侧根原基。 同样，人们对某些中柱鞘细胞如何选择增殖而其邻居保持静止的情况知之甚少。 最后，尚不清楚如何感知外部条件以及如何将信息整合到有关何时何地形成新侧根的决策中。 该提案的目的是剖析调节侧根萌生的机制。 我们的主要策略包括分析我们最近在拟南芥中分离出的侧根起始突变体 lin1。 虽然野生型拟南芥植物在某些环境条件下会极大地抑制侧根的形成，但 lin1 突变体却保持了高度分枝的根系。 此外，lin1 显示生长素积累模式的改变，生长素是一种已知对侧根形成至关重要的激素。 我们将克隆 LIN1 基因，并使用遗传、生理和基因组方法表征 LIN1 通路。 这些研究将开始揭示植物生物学的基本谜团之一：如何做出协调植物发育与环境线索的决策？ 它们还将影响我们对植物如何在营养生长过程中选择性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营养胁迫提供重要见解，并可能导致作物能够在不利条件下生存的发展。