Regulation of plastid metabolism in higher plants

本提案的目的是提高我们对高等植物质体代谢途径调控的基本认识。特别是，该研究计划将研究油籽质体中生育酚生物合成的调控机制，发育细胞器内途径的组织，及其与其他主要代谢途径的关系。生育酚和生育三烯醇是一组重要的脂溶性抗氧化剂，仅在光合组织中合成，具有许多有益的特性，无论是对人体健康（例如维生素E活性），还是在食品工业中作为稳定剂和防腐剂，因此是大豆等主要油籽作物（甘氨酸max L.）的宝贵副产品。我们计划采用多学科的方法来了解拟南芥（一种遗传亲和性植物，也是一种油籽）叶片叶绿体和发育中的油籽（如大豆）的光异养质体中生育酚和生育三烯醇生物合成的调控和组织。具体来说，这些技术将被用于检查质体（内膜和质体胞室，如质体红蛋白）内途径的组成部分，并识别其他尚未发现的与生育酚生物合成途径组成部分相互作用的蛋白质，例如信号转导级联的调节因子或元件和质体内运输系统。本研究将为了解高等植物质体中重要代谢途径的调控机制提供重要见解，并有助于提高营养价值和提高高价值生物制品的工程作物。

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.