Molecular genetic of Plant hormone signaling

摘要：植物激素是结构上不相关的小分子的集合，对植物的生长和发育有深远的影响。在过去的十年里，在定义许多荷尔蒙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，了解这些小分子传递的信息是如何转化为细胞反应的。此外，我们还进入了一个阶段，需要将来自实验模型的信息转化为重要的作物。我的研究项目调查了两种植物激素，脱落酸(ABA)和木犀草酮(SLS)在萌发和早期幼苗生长方面的基本机制。在这里，我建议使用系统和化学生物学的尖端工具，在基础水平上和生物技术应用上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。*项目1：ABA是一种长期研究的激素，在不同的王国中调节各种发育反应。在植物中，ABA在萌发和叶片水分关系中起着关键作用。在转录水平上，ABA调节超过三分之一的植物基因组。因此，阐明由ABA控制的转录因子(TF)对于将这种激素与其控制的众多发育过程联系起来是至关重要的。在其他模型系统中，控制激活转录因子，然后监测全球基因表达，在没有任何先前生物学知识的情况下，在体内分配功能一直是一种卓有成效的策略。在以往蛋白质网络研究的基础上，我们将在拟南芥模型中使用系统方法来开发第一个细胞类型特异的ABA调控的转铁蛋白网络。这种方法应该适用于具有复杂转录输出的其他植物激素系统。*项目2：SLS形成了一类相对较新的激素，被寄生植物用作发芽信号，以协调它们的生长和宿主的生活史。一旦种植了作物，它们的根部就会分泌SLS，这种物质会刺激Striga种子的萌发，从而允许寄生虫感染并提取寄主的养分。仅在非洲，联合国就将稻瘟病菌侵扰列为非洲大陆赤贫的主要原因。因此，了解Striga如何将SLS视为萌发线索，对于制定防治这种杂草的农用化学战略至关重要。我们将建立一个高通量的化学遗传学筛选系统，以寻找与刺参SL受体结合的新型SL激动剂和拮抗剂。这些化学物质将使我们能够在不需要复杂的遗传学或转基因技术的情况下探索斯特里加的复杂的SL受体系统。此外，这些探针可以作为开发银生物技术化合物的先导，以减少斯特里加的感染。**

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.**