Regulation of plastid metabolism in higher plants

这项建议的目的是提高我们对高等植物中叶绿体代谢途径调控的基本了解。特别是，该研究计划将研究油籽叶绿体中生育酚生物合成的调控机制，发育中细胞器内该途径的组织，以及它与其他主要代谢途径的关系。生育酚和生育三烯醇是一类重要的脂溶抗氧化剂，仅在光合作用组织中合成，对人类健康(如维生素E活性)和食品工业具有许多有益的性质，作为稳定剂和防腐剂，因此是主要油料作物(如大豆)的宝贵副产品。我们计划采用多学科的方法来了解生育酚和生育三烯醇生物合成的调节和组织，包括拟南芥(一种遗传上服从遗传的植物，也是一种油料种子)的叶绿体和发育中的油籽(如大豆)的光异养质体。具体地说，这些技术将被用来检测叶绿体内途径的成分(内膜和亚质质室，如质球体)，并识别其他尚未发现的与生育酚生物合成途径成分相互作用的蛋白质，例如信号转导级联和质内运输系统的调节因子或元件。这项研究将为控制和调控高等植物体内重要代谢途径的机制提供重要的见解，并有助于开发具有更高营养价值的工程作物和增强高价值的生物制品。

The objective of this proposal is to improve our fundamental understanding of the regulation of plastid metabolic pathways in higher plants. In particular, the research program will investigate the regulatory mechanisms governing tocopherol biosynthesis in oilseed plastids, the organization of the pathway within developing organelles, and its relationship to other major metabolic pathways. Tocopherols and tocotrienols are an important group of lipid-soluble antioxidants synthesized exclusively in photosynthetic tissues, with many beneficial properties, both with respect to human health (e.g. vitamin E activity), and within the food industry as stabilizers and preservatives, and are therefore a valuable by-product of major oilseed crops such as soybean (Glycine max L.). We plan to take multi-disciplinary approaches to understanding the regulation and organization of tocopherol and tocotrienol biosynthesis both in leaf chloroplasts of Arabidopsis (a genetically amenable plant and also an oilseed) and photoheterotrophic plastids of developing oilseeds such as soybean. Specifically, these techniques will be employed to examine the components of the pathway within plastids (inner membranes, and sub-plastidial compartments such as the plastoglobules), and identify other, as yet undiscovered, proteins interacting with components of the tocopherol biosynthetic pathway, e.g. regulatory factors or elements of signal transduction cascades and intra-plastidial trafficking systems. This research will provide important insights into the mechanisms governing the control and regulation of important metabolic pathways in the plastids of higher plants, and contribute to engineering crops with improved nutritional value and enhanced high-value bioproducts.