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.

非技术性总结：制定提高作物生产力的战略，以满足日益增长的社会对粮食供应和替代能源的需求，这对当前和未来的植物研究提出了挑战。此外，平衡摄入必需营养素或代谢物对全世界的人类营养很重要，但其含量在作物物种中往往不是最佳的，豆类种子中的必需氨基酸甲硫氨酸就是如此。在高等植物中，碳和氮在数量上是植物发育最重要的营养物质。大量营养素被植物吸收并被同化为蔗糖和氨基酸。然后这些物质在维管系统中被运输到种子中，以支持种子的生长和储存储备的积累，如蛋白质，淀粉或油。本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，并克服同化物运输的潜在瓶颈。本研究将为转运蛋白在向种子输送碳氮营养物质中的作用及其在种子产量和营养品质中的关键作用提供线索。项目技术说明：氨基酸和蔗糖转运蛋白的转基因修饰已突出了它们在同化物分配中的重要作用;然而，将转运蛋白功能与种子发育、种子代谢种子贮藏化合物的合成及其营养品质。目前的数据表明，长距离运输途径中的瓶颈在于叶片（即韧皮部）和胚中的转运活性或缺乏转运活性。此外，研究支持氮同化物转运蛋白在其功能的上游和下游的代谢过程中进行强有力的调控。本研究以豌豆（Pisum sativum L.）(pea)将被用作模型系统。将分析转基因植物，其中光合同化物转运蛋白在韧皮部和子叶转移细胞中同时过表达，在子叶转移细胞中发生同化物输入到胚中。潜在的限制将克服源库运输的光合同化物，以促进库的发展和种子贮藏产品的积累（目标1），并解决如果和如何不同的胚胎吸收系统影响种子同化物通量，代谢和代谢物区室化（目标2）。分子，生物化学和细胞生物学分析，和生理技术，以及磁共振成像（MRI）的结合，在生活中的种子和建模方法同化通量的研究将被用来回答一些长期存在的问题，同化物转移的速率限制和监管过程中，分布和使用内，主要的胚胎存储网站。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进行研究，让学生参与国际合作，以及通过有当地社区参与的示范和活动，进一步促进学生和公众在植物生物学方面的教育。总体而言，该项目将促进植物生物学教育和研究的有效整合。