Evolutionary analysis of heterotrimeric G-protein function in plants

智力优势：由Galpha、Gbeta和GGamma亚基组成的异三聚体G蛋白调节真核生物中一些最重要的信号通路。在后生动物中，进化的多样化导致了大量G蛋白和相关成分的存在，这些G蛋白和相关成分以高度特异性调节多种信号通路。相比之下，植物的G蛋白数量非常有限，它们整合了过多的信号通路来调节整体生长和发育。这一观察结果导致了一种假设，即植物G蛋白的进化与后生动物的G蛋白不同，与植物的久坐生活方式相一致。目前对植物G蛋白结构/功能属性的详细研究大多局限于拟南芥，这限制了人们对植物G蛋白在进化过程中为什么以及何时作为多种信号的调节器而出现的了解。目前也不知道G-蛋白是否已经进化到在特定植物谱系特有的生物过程中发挥关键作用。此外，植物中某些非常规G蛋白成分的存在表明它们在调节新的、迄今尚未探索的G蛋白信号机制中发挥了作用(S)。在重要的进化节点处，许多植物物种的全序列基因组的可用性，以及PI使用生化、分子遗传学和基因组/蛋白质组规模分析等补充方法处理G蛋白信号的丰富经验，使她在解决与植物G蛋白信号相关的一些关键问题方面处于有利地位。为此，已从拟南芥、水稻、大豆、商陆、卷柏、短柄蕨属和水杨属植物中获得了与G蛋白组分及其活性相关的重要初步数据。这项研究的总体目标是了解G蛋白核心组分的功能进化及其在植物中的相互作用，并推断传统的和新的信号机制及其在调节植物适应和产量的信号途径中的作用。为了实现这一目标，将追求以下具体目标：目标1.在进化多样化的背景下对G-蛋白复合体的酶活性蛋白进行生化表征目标2.评估来自不同类群的G-蛋白在调节陆地植物进化中重要的信号通路中的作用。这项研究产生的材料和智力资源将通过拟南芥资源中心和我们的网站公开提供。这项研究的长期益处包括全面了解植物中G蛋白成分和信号机制的进化，以及它们在控制重要农艺性状的调控途径中的作用。更广泛的影响：这项研究解决了植物信号和进化的基本方面。鉴于G蛋白参与调节重要农艺性状，如种子发育和生理、非生物胁迫耐受性和水分利用效率，本研究获得的知识将有助于对重要农业性状进行工程设计，以造福社会。此外，该研究还特别纳入了通过STAR计划对高中生和教师进行的培训，以及通过REU计划对本科生进行的培训。作为丹福斯中心REU项目的联合主任，PI积极参与本科生的招聘、指导和培训；通过参与华盛顿大学植物生物学招聘、论文委员会和教学，积极参与研究生的招聘、指导和培训。这项拟议的研究为博士后提供现代植物生物学各个方面的多学科培训。该协会致力于为博士后提供培训和指导机会，帮助他们建立独立的职业生涯。该中心透过多项义工计划，积极参与培养当地社区的科学意识，包括参与“远问植物科学家”专栏和“远方对话”系列，为当地公众和科学家提供互动环节。

Intellectual Merit: Heterotrimeric G-proteins consisting of Galpha, Gbeta and Ggamma subunits regulate some of the most important signaling pathways in eukaryotes. In metazoans, evolutionary diversification has led to the presence of a large number of G-proteins and associated components that regulate a multitude of signaling pathways with a high degree of specificity. In contrast, plants have a very limited number of G-proteins that integrate a plethora of signaling pathways to modulate overall growth and development. This observation has led to the hypothesis that the plant G-proteins have evolved differently from the metazoan G-proteins in accordance with the sedentary lifestyle of plants. Detailed studies of the structure/function attributes of plant G-proteins is currently mostly limited to Arabidopsis which restricts the knowledge of why and when during evolution the plant G-proteins emerged as modulators of multiple signals. It is also not known if the G-proteins have evolved to play critical roles in biological processes that are unique to specific plant lineages. Furthermore, the presence of certain unconventional G-protein components in plants suggests their role(s) in regulating novel, as yet unexplored G-proteins signaling mechanisms. The availability of fully sequenced genomes from a number of plant species at important evolutionary nodes and the PIs extensive experience working with G-protein signaling using complementary approaches including biochemical, molecular-genetics and genome/proteome-scale analyses, puts her in an excellent position to address some of the key questions related to the plant G-protein signaling. Towards this, important preliminary data have been generated related to G-proteins components and their activity from Arabidopsis, rice, soybean, Physcomitrella, Selaginella, Brachypodium and Aquilegia. This research has been developed with the overall objective to understand the functional evolution of the G-protein core components and their interaction in plants, and to infer the conventional and novel signaling mechanisms and their role in regulating signaling pathways involved in plant adaptation and yield. To accomplish this objective, following specific aims will be pursued: Aim 1. Biochemical characterization of the enzymatically active proteins of the G-protein complex in the context of their evolutionary diversification Aim 2. Evaluation of the role of G-proteins from across different taxa in regulating the signaling pathways important in the context of land plant evolution The material and intellectual resources generated from this research will be made publicly available through the Arabidopsis stock center and through our website. The long term benefits of the research include comprehensive knowledge of the evolution of G-protein components and signaling mechanisms in plants and their roles in regulating pathways controlling agronomically important traits. Broader Impact: This research addresses the fundamental aspects of plant signaling and evolution. Given the involvement of G-protein in regulating important agronomic traits such as seed development and physiology, abiotic stress tolerance and water use efficiency, the knowledge gained from this research will be useful for engineering important agricultural traits to the benefit of society. Moreover, the research specifically incorporates training for high-school students and teachers through the STARS program and undergraduate students through the REU program. The PI is actively involved in recruiting, mentoring and training of undergraduate students as a co-director of the Danforth Center REU program; and graduate students through her participation in Washington University plant biology recruitment, thesis committees and teaching. The proposed research offers multidisciplinary training to the post-docs in various aspects of modern plant biology. The PI is strongly committed to provide training and mentoring opportunities to post-docs to help them establish their independent careers. The PI is actively involved in developing scientific awareness in the local community through multiple volunteering programs offered at the Center, including participation in the ¡¥Ask a Plant Scientist¡¦ column and ¡¥Conversations¡¦ series, which offers an interactive session between local public and scientists.