CAREER: Influence of Amino-Acid Transport and Partitioning on Nitrogen Profiles in Legume Seeds

本项目将发展和加强研究植物体内氮的分布和运输的研究和教学计划。氮在大多数植物中的主要运输形式是氨基酸，这是合成酶和蛋白质的基本组成部分。这些代谢物对植物生长至关重要，也直接或作为动物饲料对人类营养起着重要作用。许多作物的经济和营养价值与它们积累的蛋白质的数量和质量有关，这取决于氨基酸从合成位点的运输。然而，调节氨基酸从叶或根的产生位点（来源）到利用位点（如种子（汇））的运输或分配的机制尚不清楚。这个项目的假设是，各种氨基酸在叶片和种子之间的分配是由位于源细胞和汇细胞中的特定转运体控制的。选择豌豆作为模型，因为它具有大的种子，并且提供了负责氨基酸进口的质膜运输事件的实验途径。氨基酸转运体负责摄取广泛的氨基酸在豌豆将分析其细胞定位和功能。转运过程将通过在源和库器官中过表达转运蛋白来控制，然后分析对氨基酸转运到种子和氮组成的影响。转基因豌豆植物将为探索氨基酸分配的调控以及特定氨基酸的运输如何影响生长和种子组成等问题提供极好的工具。获得的信息可以潜在地转移到其他作物，以确保植物生产力和提高用作食物的种子或其他植物器官的营养质量。该项目将为氨基酸分配到沉器官（如种子）的基本过程提供重要的新数据，并将为未来的策略提供平台，旨在操纵作物植物中氨基酸和蛋白质的质量和数量。它还将通过将研究技术和结果纳入首席研究员教授的本科和研究生课程，大力促进各级学生在植物生物学方面的教学和培训。这些课程将为学生提供前沿的研究和技术信息。暑期课程津贴将提供给四名之前参加过PI植物生理学课程的优秀本科生，他们将参与项目的特定部分，以获得植物分子生理学的第一手经验。研究生和研究生将参与本科生辅导和研究。该项目将促进各级植物生物学教育和研究的有效整合，促进PI的专业发展，并为该系和学生的植物科学培训做出贡献。

This CAREER project will develop and strengthen a research and teaching program studying distribution and transport of nitrogen in plants. The major transport form of nitrogen in most plants is as amino acids, which are the basic building blocks for synthesis of enzymes and proteins. These metabolites are crucial for plant growth and also play a significant role for human nutrition either directly or as feed for animals. The economic and nutritional value of many crops is related to the amount and quality of proteins they accumulate, which is dependent upon transport of amino acids from sites of synthesis. However, the mechanisms regulating transport or partitioning of amino acids from sites of production in leaves or roots (source) to sites of utilization such as seeds (sinks) are not well understood. The hypothesis underlying this project is that partitioning of various amino acids between leaves and seeds is controlled by specific transporters located in the source and sink cells. Pea has been chosen as a model as it has large seeds and provides experimental access to the plasma membrane transport events responsible for amino acid import.Amino acid transporters responsible for uptake of a broad range of amino acids in pea will be analyzed with respect to their cellular localization and function. Transport processes will be manipulated by overexpressing the transporters in source and sink organs followed by analysis of effects on amino acid translocation to seeds and on nitrogen composition. The genetically-modified pea plants will provide excellent tools to explore questions about the regulation of partitioning of amino acids, and how transport of specific amino acids can affect growth and seed composition. The information gained can potentially be transferred to other crops to ensure plant productivity and enhance nutritional quality of seeds or other plant organs used as food. Broader ImpactThis CAREER project will generate important new data on the fundamental processes of amino acid allocation to sink organs (e.g. seeds), and will provide the platform for future strategies aimed at manipulating amino acid and protein quality and quantity in crop plants. It will also strongly promote teaching and training of students in plant biology at all educational levels through incorporation of the research techniques and results into undergraduate and graduate level courses taught by the principal investigator (PI). These courses will provide cutting-edge research and technology information to the students. A summer course stipend will be offered to four top undergraduate students who have previously taken the PI's Plant Physiology course for work on specific parts of the project to gain first hand experience in plant molecular physiology. A graduate and postgraduate student will be involved in undergraduate tutoring and research. The project will promote effective integration of plant biology education and research at all levels and advance the PI's professional development and her contribution to the department and to student training in plant science.