Molecular genetic of Plant hormone signaling

植物激素是一组结构上不相关的小分子，对植物的生长和发育有着深远的影响。在过去的十年中，在确定许多激素的核心信号通路方面取得了令人兴奋的进展。现在植物激素生物学正在进入一个具有挑战性的时期，即了解这些小分子传递的信息如何转化为细胞反应。此外，我们也正在进入一个阶段，需要将实验模型的信息转化为重要作物。我的研究计划调查两种植物激素，脱落酸（阿坝）和独脚金内酯（SL）的发芽和早期幼苗生长的基本机制。在这里，我建议使用系统和化学生物学的尖端工具，以新颖的方式将这些激素与植物生长和发育网络联系起来，无论是在基础层面还是在生物技术应用方面。 项目1：阿坝是一种长期研究的激素，它介导各种王国的发育反应。在植物中，阿坝是萌发和叶水关系的关键角色。在转录水平上，阿坝调节植物基因组的三分之一以上。因此，阐明由阿坝控制的转录因子（TF）对于将这种激素与其控制的许多发育过程联系起来至关重要。在其他模型系统中，TF的受控激活，然后监测全局基因表达，是在没有任何先验生物学知识的情况下在体内分配功能的富有成效的策略。在前人蛋白质网络研究的基础上，我们将利用系统方法在拟南芥中构建第一个细胞类型特异的阿坝调控的TF网络。该方法应适用于其他植物激素系统，具有复杂的转录输出。 项目二：SL形成了一类相对较新的激素，它们被独脚金属的寄生植物用作萌发线索，以使它们的生长与宿主的生活周期相协调。一旦作物种植，它们的根分泌SL，其作用是刺激独脚金种子萌发，从而使寄生虫感染并吸收宿主营养。仅在非洲，联合国就将Striga hermonthica侵扰列为非洲大陆赤贫的主要原因。因此，了解Striga如何将SL视为发芽线索，对于制定农业化学策略来对抗这种杂草至关重要。我们将建立一个高通量的化学遗传学筛选系统，以确定新的SL激动剂和拮抗剂结合SL受体在独脚金。这些化学物质将使我们能够探测Striga中复杂的SL受体系统，而不需要复杂的遗传学或转基因技术。此外，这些探针可用作开发Ag-生物技术化合物以减少独脚金侵扰的先导。

Summary: Plant hormones are a collection of small structurally unrelated molecules that have profound effects on plant growth and development. Over the past decade, exciting advances have been made to define core-signaling pathways for many hormones. Now plant hormone biology is entering a challenging period of understanding how the information conveyed by these small molecules is turned into cellular responses. Furthermore, we are also entering a stage where information from experimental models needs to be translated to important crops. My research program investigates the fundamental mechanisms of two plant hormones, abscisic acid (ABA) and strigolactones (SLs) with respect to germination and early seedling growth. Here, I propose to use the cutting edge tools of systems and chemical biology to link these hormones to plant growth and development networks in novel ways both at a fundamental level and for biotechnological application. Project 1: ABA is a long studied hormone that mediates an assortment of developmental responses across a variety of kingdoms. In plants, ABA is a key player in germination and leaf water relations. At a transcriptional level, ABA regulates over a third of a plant’s genome. Thus, the elucidation of the transcription factors (TFs) that are controlled by ABA is critical to linking this hormone to the numerous developmental processes that it controls. In other model systems, controlled activation of TFs followed by monitoring of global gene expression has been a fruitful strategy in assigning functionality in vivo without any prior biological knowledge. Building on previous protein network studies, we will use systems approaches in the model Arabidopsis to develop the first cell type specific ABA regulated TF network. The approach should be adaptable to other plant hormone systems, which have complicated transcriptional outputs. Project 2: SLs form a relatively new class of hormones that are used as a germination cue by parasitic plants of the Striga genera to coordinate their growth with a host’s life cycle. Once crops are planted, their roots exude SLs, which act to stimulate Striga seed germination thereby allowing the parasite to infect and withdraw host nutrients. In Africa alone, the UN classifies Striga hermonthica infestations as the major cause of abject poverty on the continent. Understanding how Striga perceives SLs as a germination cue is therefore essential to developing agro-chemical strategies to combating this weed. We will establish a high throughput chemical genetics screening system to identify novel SL agonists and antagonists that bind SL receptors in Striga hermonthica. These chemicals will allow us to probe the complex SL receptor system in Striga without the need of sophisticated genetics or transgenic technologies. Furthermore, these probes can be used as leads in the development of Ag-biotech compounds to decrease Striga infestations.