RUI: Assessing C4-pathway regulation by the pyruvate phosphate dikinase regulatory protein in maize leaves

RUI：评估玉米叶中丙酮酸磷酸二激酶调节蛋白对 C4 途径的调节

• 批准号: 0956516
• 负责人: Chris Chastain
• 金额: $ 7.5万
• 依托单位: Minnesota State University Moorhead
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-03-01 至 2013-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0956516&HistoricalAwards=false
• 关键词: RUI; Assessing; C4; pathway; regulation

Almost all plants fix CO2 into carbohydrate using an ancient photosynthetic process termed C3 photosynthesis (i.e., C3 plants). A subset of plants utilize a more efficient photosynthetic process termed C4 photosynthesis (i.e., C4 plants). In open sunny environments the rate of CO2 fixation, biomass accumulation, and grain yield in C4 plants is nearly twice that of C3 plants. The increased photosynthetic performance of C4 versus C3 plants is due in part to the evolution of an additional set of photosynthetic CO2 fixation enzymes referred to as the C4 pathway. Despite the inherently higher productivity of C4 versus C3 plants, there are only four agronomically important C4 crop species: maize, Sorghum, sugar cane, and switch grass. All other crop species (e.g., rice, soybean, wheat) are C3 plants. Thus an ongoing research goal of plant scientists is to breed or engineer C4 photosynthesis into C3 crop plants for improving yields. Efforts to date have fallen short in part because of the lack of understanding on how the C4 pathway is controlled in leaves for optimizing use of available sunlight. The ultimate aim of this project is to elucidate how such regulation works. A first step in this endeavor, and the goal of this one-year project, is to develop maize plants that are deficient in two interrelated light-responsive C4 pathway enzymes, pyruvate phosphate dikinase (PPDK) and the PPDK regulatory protein (RP). It is hypothesized that these enzymes control the rate of the CO2 fixation by the C4 pathway in response to sunlight. Using RNA interference, a genetic engineering method, stable lines of maize plants will be isolated with reduced levels of PPDK or RP enzyme. These plants will be subsequently assessed for photosynthetic performance. From these analyses, an accurate picture of how PPDK and RP confer sunlight-responsive C4 pathway regulation is expected to emerge. This knowledge will be critical for projects now underway that seek to introduce a functional C4 pathway into leaves of C3 crop species. A major education and training component of the project is the participation of undergraduate Biochemistry/Biotechnology degree students in fulfillment of their senior thesis research requirement.

几乎所有植物都使用称为 C3 光合作用的古老光合作用过程（即 C3 植物）将 CO2 固定为碳水化合物。一部分植物利用更有效的光合作用过程，称为 C4 光合作用（即 C4 植物）。在阳光充足的开放环境中，C4 植物的二氧化碳固定率、生物量积累和谷物产量几乎是 C3 植物的两倍。与 C3 植物相比，C4 植物光合作用性能的提高部分归因于一组额外的光合 CO2 固定酶（称为 C4 途径）的进化。尽管 C4 植物本质上比 C3 植物具有更高的生产力，但只有四种具有重要农艺意义的 C4 作物品种：玉米、高粱、甘蔗和柳枝稷。所有其他作物品种（例如水稻、大豆、小麦）都是 C3 植物。因此，植物科学家正在进行的研究目标是将 C4 光合作用培育或改造为 C3 作物，以提高产量。迄今为止的努力未能成功，部分原因是缺乏对如何控制叶子中的 C4 途径以优化可用阳光的利用的了解。该项目的最终目标是阐明此类监管如何运作。这项工作的第一步，也是这个为期一年的项目的目标，是培育缺乏两种相互关联的光响应 C4 途径酶——丙酮酸磷酸二激酶 (PPDK) 和 PPDK 调节蛋白 (RP) 的玉米植物。据推测，这些酶通过 C4 途径控制 CO2 固定速率，以响应阳光。使用 RNA 干扰（一种基因工程方法），将分离出 PPDK 或 RP 酶水平降低的稳定玉米植株系。随后将评估这些植物的光合作用性能。从这些分析中，预计将出现关于 PPDK 和 RP 如何赋予阳光响应性 C4 通路调节的准确图像。这些知识对于目前正在进行的旨在将功能性 C4 途径引入 C3 作物物种叶子的项目至关重要。 该项目的一个主要教育和培训组成部分是本科生生物化学/生物技术学位学生的参与，以满足他们的高级论文研究要求。