Sorting of seed storage proteins in developing seeds: Formation of transport vesicles and interdependence of different sorting pathways

植物种子贮藏蛋白直接或间接作为主食，对人类的营养是必不可少的。贮藏蛋白质可占种子干重的30%以上。在双子叶植物如豆科植物和油菜的成熟过程中，种子贮藏蛋白质沉积在发育中的胚中的特化液泡中，蛋白质贮藏液泡。蛋白质通过不同的囊泡运输途径、网格蛋白包被囊泡（CCV）和迄今为止独特的致密囊泡（DV）介导的途径到达这些液泡。这些途径似乎是相互依存的。本研究旨在利用免疫电镜技术，从分子水平和超微结构水平研究这两条途径在拟南芥胚胎PSV中的相互依赖性。我们将比较分子转运标记的排序与定义的液泡分选决定因素在转基因拟南芥野生型植物和缺失突变体的种子缺乏受体和胞质蛋白这两个重要的运输途径。我们将在分子水平上研究DV在顺式高尔基体的形成。我们将采用生物化学，蛋白质组学和反向遗传学的方法来识别和表征参与货物蛋白聚集的蛋白质。

Plant seed storage proteins are essential for human nutrition, either directly or indirectly as staple food. Storage proteins can make up to more than 30% of the dry weight of the seed. During maturation of dicotyledonous plants, like legumes and rape, seed storage proteins are deposited in specialized vacuoles, the protein storage vacuoles PSV), in the developing embryo. Proteins reach these vacuoles via different vesicular transport routes, the Clathrin Coated Vesicle (CCV), and the, hitherto unique, Dense Vesicle (DV) mediated pathways. These pathways appear to be interdependent. This proposal aims at investigating the interdependence of these two pathways into the PSV of Arabidopsis embryos on a molecular and ultrastructural level, employing immuno electron-microscopy. We will compare the sorting of molecular transport markers with defined vacuolar sorting determinants in seeds of transgenic Arabidopsis wild type plants and deletion mutants devoid of receptors and cytosolic proteins important for these two transport routes. We will investigate the formation of the DV at the cis-Golgi apparatus on a molecular level. We will employ biochemical, proteomic, and reverse genetic approaches to identify and characterize proteins which are involved in the aggregation of cargo proteins.