Physiological Genomics of Maize Nodal Root Growth under Drought

Pi：Robert E.Sharp(密苏里大学)Copis：David M.Braun，Felix B.Fritschi，Trupti Joshi，Scott C.Peck，Jonathan T.Stemmle(密苏里大学)和Melvin J.Oliver(USDA-ARS/密苏里大学)开发高效利用可用水的耐旱玉米品种，对于到2050年维持约90亿全球人口至关重要。玉米通过一组特殊的称为节根的根吸收大部分水分。在干旱情况下，节根必须通过干燥的土壤生长，以获得可用水来维持植物的生长。然而，人们对允许节根实现这一基本壮举的机制知之甚少。该项目将使用生理学和基因组学相结合的方法来确定根瘤如何能够在干旱情况下保持生长的分子机制。该项目产生的信息将导致制定创新办法，使玉米和其他谷类作物在干旱情况下能够获得更多的水并提高产量，从而有助于实现加强粮食安全和稳定的基本目标。除了培训学生和博士后，该项目还将为福特谷州立大学的本科生提供暑期研究培训实习机会，福特谷州立大学是一所历史悠久的黑人大学(HBCU)，位于佐治亚州福特谷。该项目还将通过各种交流、技术培训和外联活动向公众传播研究成果和提供信息。这些活动包括但不限于由新闻系学生参加的科学交流讲习班，以及代谢组学实践培训讲习班，以及使用生物信息学工具分析和整合多组学数据集。该项目结合了根生理学和功能基因组学[转录组学、质膜蛋白质组学和代谢组学(包括激素)]，在对照实验室研究和田间试验中全面了解根瘤对水分胁迫的反应。该项目的重点是一个玉米自交系，该自交系已被证明在水分有限的条件下表现出优越的节根生长能力。一个合作的跨学科小组将涉及下列具体目标：1)利用一种新型的分室模型系统精确地施加生长根周围的水分胁迫条件，阐明节根生长对水分胁迫的生理和分子基础；2)利用“干旱模拟器”精确地施加干旱的时间、强度和持续时间，表征根节生长和根生长带对田间水分胁迫的反应；以及3)利用一套信息学工具整合和分析所有数据集，以确定将在植物中得到遗传验证的候选基因。这一多学科战略提供了独特的机会，极大地提高了对干旱下的根生物学的基本理解，并广泛培训了下一代植物科学家。该项目产生的数据和生物材料将可进入项目网站(待开发)，并通过存放到长期储存库，如玉米遗传合作社(种质)、MaizeGDB、Gramene和NCBI的GEO和SRA(用于序列和表型数据集)。

PI: Robert E. Sharp (University of Missouri)CoPIs: David M. Braun, Felix B. Fritschi, Trupti Joshi, Scott C. Peck, Jonathan T. Stemmle (University of Missouri) and Melvin J. Oliver (USDA-ARS/University of Missouri) Developing drought-tolerant corn varieties that make efficient use of available water is vital to sustain the estimated 9 billion global population by 2050. Corn takes up most of its water through a particular set of roots called the nodal roots. Under drought, the nodal roots must grow through dry soil to reach available water to sustain the plant. However, very little is known about the mechanisms that allow nodal roots to achieve this essential feat. This project will use a combination of physiological and genomics approaches to define the molecular mechanisms underlying how the nodal roots are able to maintain growth under drought. The information generated by the project will lead to the development of innovative approaches to enable corn and other cereal crops to access more water and increase yield under drought, and will thereby contribute to the essential goals of increased food security and stability. In addition to the training of students and postdoctoral associates, the project will provide summer research training internships for undergraduate students from Fort Valley State University, a Historically Black University (HBCU) located in Fort Valley (GA). The project will also disseminate research findings and provide information to the general public through various communication, technical training and outreach activities. These include but are not limited to science communication workshops involving journalism students and hands-on training workshops on metabolomics and the use of bioinformatics tools to analyze and integrate multi-omics datasets. This project integrates root physiology and functional genomics [transcriptomics, plasma membrane proteomics, and metabolomics (including hormones)] to deliver a comprehensive understanding of nodal root growth responses to water deficit stress in both controlled laboratory studies and in the field. The project focuses on a maize inbred line that has been shown to exhibit superior ability for nodal root growth under water-limited conditions. A collaborative interdisciplinary team will address the following specific objectives: 1) elucidation of the physiological and molecular basis of nodal root growth responses to water stress using a novel divided-chamber model system for precise imposition of water deficit conditions around the growing roots; 2) characterization of nodal root growth and root growth zone transcriptomic responses in response to water stress in the field, using "drought simulators" for precise imposition of the timing, intensity and duration of drought; and 3) integration and analysis of all datasets using a suite of informatics tools to identify candidate genes that will be genetically validated in plants. This multidisciplinary strategy provides unique opportunities to greatly improve basic understanding of root biology under drought, and to broadly train the next generation of plant scientists. Data and biological materials generated by this project will be accessible to a project website (to be developed) and through deposition to long-term repositories such as the Maize Genetics Cooperative (for germplasm), and MaizeGDB, Gramene and the NCBI's GEO and SRA (for sequence and phenotypic datasets).