Hexose Transporter Genes and the Origin of Land Plants

9628869格雷厄姆陆地植物，就像动物一样，从形成胚胎开始生命。陆地植物胚胎，像许多但不是所有的动物胚胎一样，在与父母相连的情况下发育，从父母那里获得食物，特别是糖。与糖运输相关的遗传机制还不是很清楚，特别是在形态简单的植物中，如苔藓(苔藓、地钱、角藻)，它们有胚胎，以及轮叶绿藻，它们与苔藓关系密切，但没有胚胎。在这项研究中，琳达·格雷厄姆和李·威尔科克斯将开始对一组基因--己糖转运蛋白基因家族--进行评估，这些基因与植物中的糖运输有关。他们将从轮藻中的己糖转运蛋白基因中获得分子序列信息。他们将使用这些序列来构建系统发育树，并将这些树与其他来自不同基因序列以及植物的形态和解剖特征的树进行比较，以寻求对轮藻绿藻和苔藓植物密切相关的假设的进一步支持。他们将寻求支持这样的假设，即糖从亲本植物到胚胎的运输部分基于己糖转运蛋白基因产物(即蛋白质)，这些基因产物来自没有胚胎的植物(轮藻绿藻)，但在苔藓植物中亲本植物和发育中的胚胎的连接处特异表达。这些结果将为陆地植物胚胎的起源、早期历史和发育提供重要的新信息，陆地植物胚胎是陆地植物生活史上最重要的事件之一。

9628869 GRAHAM Land plants, like animals, begin life by forming embryos. Land plant embryos, like many but not all animal embryos, develop while attached to a parent from which they obtain food, especially sugars. The genetic mechanisms associated with sugar transport are not well understood, especially in morphologically simple plants such as bryophytes (mosses, liverworts, hornworts), which have embryos, and charophycean green algae, which are closely related to mosses but do not have embryos. In this study, Linda Graham and Lee Wilcox will begin an evaluation of one set of genes, the hexose transporter gene family, that are involved in sugar transport in plants. They will obtain molecular sequence information from hexose transporter genes in charophycean green algae. They will use these sequences to construct phylogenetic trees, and compare these trees with others derived from sequences of different genes, and from the morphological and anatomical features of the plants, seeking additional support for the hypothesis that charophycean green algae and bryophytes are closely related. They will seek support for the hypothesis that sugar transport from parent plant to embryo is based in part upon hexose transporter gene products (i.e., proteins) that are derived from plants without embryos (charophycean green algae) but are specifically expressed at the junction between parent plant and developing embryo in bryophytes. The results should provide significant new information on the origin, early history, and development of the land plant embryo, one of the most fundamentally important events in the life history of land plants.