Integrating Photoassimilate Source to Sink Transport in Legumes to Enhance Seed Development and Nutrition

将豆类中的光同化物源库运输整合以增强种子发育和营养

• 批准号: 1457183
• 负责人: Mechthild Tegeder
• 金额: $ 64.75万
• 依托单位: Washington State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-01 至 2020-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1457183&HistoricalAwards=false
• 关键词: Integrating; Photoassimilate; Source; Sink; Transport

Non-technical Summary:The development of strategies to improve crop productivity to meet growing societal needs for food supply and alternative sources of energy provides a challenge to current and future research on plants. In addition, the balanced intake of essential nutrients or metabolites is important for human nutrition worldwide, but their content is often sub-optimal in crop species, as is the case for the essential amino acid methionine in legume seeds. In higher plants, carbon and nitrogen are quantitatively the most important nutrients for plant development. The macronutrients are taken up by the plant and are assimilated into sucrose and amino acids. These are then transported in the vascular system to the seeds to support growth and accumulation of storage reserves such as proteins, starch, or oils. The goal of this project is to understand and manipulate carbon and nitrogen assimilate transport to legume seeds, and to overcome potential bottlenecks of assimilate movement. This study will provide clues as to how transporter proteins function in delivery of carbon and nitrogen nutrients to seeds, and on their critical role in seed yield and nutritional quality.Technical Description of the Project:Transgenic modifications of amino acid and sucrose transporters have underlined their essential roles in assimilate partitioning; however, there has been only limited success integrating transporter function with seed development, seed metabolism, and the synthesis of seed storage compounds and their nutritional quality. Current data suggest that a bottleneck within the long distance transport pathway lies in the transporter activity, or the lack of it, in both leaves (i.e. phloem) and embryos. Furthermore, research supports strong regulatory control by nitrogen assimilate transporters over metabolic processes up and downstream of their function. In this study, Pisum sativum L. (pea) will be used as a model system. Transgenic plants will be analyzed, in which photoassimilate transporters are simultaneously overexpressed in the phloem and in cotyledon transfer cells, where assimilate import into the embryo occurs. Potential constraints will be overcome in source to sink transport of photoassimilates to promote sink development and seed storage product accumulation (Aim 1) and to resolve if and how different embryo uptake systems affect seed assimilate flux, metabolism and metabolite compartmentation (Aim 2). Molecular, biochemical, and cell-biological analyses, and physiological techniques, as well as a combination of magnetic resonance imaging (MRI) for assimilate flux studies in living seeds and modeling approaches will be used to answer some long-standing questions about rate limiting and regulatory processes in assimilate transfer to, and distribution and usage within, the main embryo storage sites. The proposed activities will further promote student and public education in plant biology by discussing research schemes in the classroom, by mentoring and training undergraduate and graduate students in research, by engaging students in international collaborations, and through demonstrations and activities involving the local community. Overall, this project will foster effective integration of plant biology education and research.

非技术摘要：制定提高作物生产力的策略，以满足日益增长的社会对粮食供应和替代能源的需求，对当前和未来的植物研究提出了挑战。此外，必需营养素或代谢物的均衡摄入对于全世界人类营养很重要，但它们的含量在作物物种中往往不是最佳的，豆类种子中必需氨基酸蛋氨酸的情况就是如此。在高等植物中，碳和氮是植物发育最重要的营养物质。常量营养素被植物吸收并被同化为蔗糖和氨基酸。然后，这些物质通过维管系统运输到种子，以支持蛋白质、淀粉或油等储存储备的生长和积累。该项目的目标是了解和操纵碳和氮同化物向豆科植物种子的运输，并克服同化物运动的潜在瓶颈。这项研究将提供关于转运蛋白如何在向种子输送碳和氮养分的过程中发挥作用，以及它们在种子产量和营养质量中的关键作用提供线索。该项目的技术描述：氨基酸和蔗糖转运蛋白的转基因修饰强调了它们在同化分配中的重要作用；然而，将转运蛋白功能与种子发育、种子代谢、种子储存化合物的合成及其营养质量相结合的成功有限。目前的数据表明，长距离运输途径的瓶颈在于叶子（即韧皮部）和胚胎中的转运蛋白活性或缺乏转运蛋白活性。此外，研究支持氮同化转运蛋白对其功能上下游的代谢过程进行强有力的调节控制。在本研究中，Pisum sativum L.（豌豆）将被用作模型系统。将分析转基因植物，其中光同化物转运蛋白在韧皮部和子叶转移细胞中同时过表达，同化物输入到胚胎中发生在子叶转移细胞中。将克服光同化物从源到库运输的潜在限制，以促进库发育和种子储存产物积累（目标 1），并解决不同胚胎摄取系统是否以及如何影响种子同化物通量、代谢和代谢物区室（目标 2）。分子、生物化学和细胞生物学分析以及生理技术，以及用于活体种子同化通量研究的磁共振成像（MRI）和建模方法的结合，将被用来回答一些长期存在的问题，即同化物转移到主要胚胎储存地点、在主要胚胎储存地点内的分配和使用的速率限制和调节过程。拟议的活动将通过在课堂上讨论研究计划、指导和培训本科生和研究生的研究、让学生参与国际合作以及涉及当地社区的示范和活动，进一步促进学生和公众对植物生物学的教育。总体而言，该项目将促进植物生物学教育和研究的有效结合。