Mechanisms of Sucrose Transport in the Soybean Cotyledon

影响植物生长、发育和生产力的最重要的事件之一是光合作用产物在植物各器官中的分布，通常是糖分子。这种分布依赖于调节糖在植物细胞质膜上的运输。据推测，这一过程涉及载体分子，然而，人们对载体分子本身知之甚少。最近，Grimes博士和Hitz博士及其合作者已经鉴定并克隆了一种质膜蛋白，该蛋白似乎具有作为蔗糖转运蛋白的所有正确特征。在这个项目中，Grimes博士和Hitz博士将使用包括膜生理学、蛋白质分析、基因工程和免疫学在内的各种方法，进一步表征这种被称为62SBP的蛋白质的性质和作用。他们还将与德国的一个小组合作，该小组已经发现了另一种似乎在蔗糖运输中发挥作用的膜蛋白。人们普遍认为蔗糖转运系统是一个复杂的系统，由几个组成部分组成。因此，这一合作可能会增加我们对高等植物蔗糖运输过程的理解的机会。这个项目的主要实验系统是大豆子叶，因为大豆子叶中几乎所有的细胞都在积极地运输蔗糖。该项目的成功完成将为进一步研究植物分配其光合作用产物的机制提供工具，最终将有助于我们理解植物的生长发育机制。

One of the most important events that have impact on plant growth, development, and productivity is the distribution of photosynthetic products, usually sugar molecules, throughout the organs of the plant. The distribution depends on regulating sugar transport across the plasma membrane of plant cells. It has been speculated that this process involves carrier molecules, however, very little is known about the carrier molecules themselves. Recently, Drs. Grimes and Hitz and their collaborators have identified and cloned a plasma membrane protein that appears to possess all the right characteristics to be a sucrose transporter. In this project, Drs. Grimes and Hitz will further characterize the nature and role of this protein, called 62 SBP, using various approaches including membrane physiology, protein analysis, genetic engineering and immunology. They will also collaborate with a group in Germany who has identified another membrane protein that appears to play a role in sucrose transport. It is generally believed that sucrose transport system is complex, consisting of several components. Therefore, this collaboration is likely to enhance the opportunity to advance our understanding of the sucrose transport process in higher plants. The primary experimental system for this project is soybean cotyledon as virtually all of the cells in the soybean cotyledon are actively transporting sucrose. Successful completion of this project will provide a tool to further studies of the mechanisms by which plants distribute their photosynthetic products, which will ultimately contribute to our understanding of the mechanisms of growth and development in plants.