Exocyst-Mediated Pathways to the Plant Cell Surface

这个项目试图了解植物细胞控制蛋白质和其他功能分子向外表面输送的机制，外表面是由质膜和周围细胞壁定义的区域。这一过程被称为囊泡运输，因为蛋白质在细胞内产生，包装成小的、膜结合的载体(囊泡)，然后移动到质膜进行最终传递。这一过程之所以重要，是因为：1)它是建立和控制植物细胞与外界环境相互作用的主要机制，它可以影响植物与有害或有益微生物的相互作用；2)它对细胞生长至关重要；3)它是细胞间通讯的调节器；4)它是通过特殊的质膜定位蛋白转运蛋白从周围环境中获取营养的关键。关于囊泡运输如何被控制的分子机制还不是很清楚。在植物细胞中，一个似乎可能控制这一过程的角色是八蛋白外囊复合体，它在质膜上为囊泡运输提供空间调节。本课题以拟南芥根毛为模型，研究了胞外囊介导的囊泡运输途径。EMVT是根毛正常生长所必需的，根毛是获取营养的关键结构。该项目试图通过以下途径了解根毛生长是如何依赖EMVT的：1)胞囊与囊泡运输系统的其他已知成分相互作用的特征；以及2)与拟南芥根毛中的胞囊相互作用的新基因(NERD1)的分子鉴定。该项目应该更深入地了解质膜靶标分子的功能是如何启用和控制的，以及细胞生长的精确模式是如何受到影响的。BROADER IMPACT该项目产生的知识可能对植物生理学和发育具有广泛的影响。由于其与质膜的假设连接，EMVT可能有助于调节根和土壤之间的相互作用。因此，这项工作可以为寻求管理植物对周围环境(如干旱、盐碱和营养贫瘠的土壤)引起的非生物胁迫、对病原体以及与根际微生物群落相互作用的反应的应用工作提供信息。此外，该项目将培训一名整合遗传学、细胞生物学和下一代测序方法的博士后研究人员，并将指导本科生进行植物遗传学研究。最后，该项目将通过俄勒冈州立大学的科学和工程学徒计划支持对高中生的外展努力。

INTELLECTUAL MERITThis project seeks to understand the mechanisms by which plant cells control the delivery of proteins and other functional molecules to their outer surface, the region defined by the plasma membrane and surrounding cell wall. This process is known as vesicle trafficking, as proteins are produced within the cell, packaged into small, membrane-bound carriers (vesicles), and then moved to the plasma membrane for final delivery. This process is important because: 1) it is the primary mechanism used to build and to control the plant cell interface with its outside environment, which can affect how the plant interacts with harmful or beneficial microbes; 2) it is crucial for cell growth; 3) it is a regulator of cell-cell communication between cells; and 4) it is crucial for the acquisition of nutrients from the surrounding environment via specialized plasma membrane-localized protein transporters. The molecular mechanisms regarding how vesicle trafficking are controlled are not well understood. One player that appears likely to control this process in plant cells is the eight-protein exocyst complex, which provides spatial regulation at the plasma membrane for vesicle trafficking. This project uses the Arabidopsis root hair as a model and investigates the exocyst-mediated vesicle trafficking pathway (EMVT). EMVT is required for proper growth of the root hair, a key structure for nutrient acquisition. The project seeks to understand how root hair growth relies on EMVT through: 1) Characterization of exocyst interactions with other known components of the vesicle trafficking system; and 2) Molecular identification of a new gene (NERD1) which interacts functionally with the exocyst in the Arabidopsis root hair. The project should build a deeper understanding of how the function of plasma membrane-targeted molecules is enabled and controlled, and how precise patterns of cellular growth are affected.BROADER IMPACTSThe knowledge generated in this project may have broad implications for plant physiology and development. Due to its hypothesized connection to the plasma membrane, EMVT may help mediate interactions between root and soil. Thus, this work could inform applied work that seeks to manage plant responses to abiotic stress induced by the surrounding environment (e.g. drought, salinity, and nutrient-poor soils), to pathogens, and to interactions with the rhizosphere microbial community. In addition, the project will train a postdoctoral researcher in integrating genetic, cell biological and next-generation sequencing approaches, and will mentor undergraduate students in plant genetic research. Finally, this project will support outreach efforts to high school students through the Apprenticeships in Science and Engineering program at Oregon State University.