RUI: The cell biology of pectin dynamics in the Charophycean Green Algae: Homogalacturonan secretion in the model organism, Penium margaritaceum

智能优点细胞壁聚合物是绿色植物生长、发育和生存过程中的重要生物化学物质，是地球上最丰富的生物化学物质。果胶是细胞壁聚合物的主要类别之一，在调节细胞壁的扩张和细胞生长以及调节细胞壁的孔隙度和吸收关键离子方面起着重要作用。果胶的合成、分泌和分泌后重塑是植物细胞生命中的关键亚细胞事件，阐明这些过程的具体研究才刚刚开始。果胶存在于所有陆地植物群中，最近在查尔逊绿藻(CGA)中得到了表征。CGA代表了现存的绿藻种群，它们是现代陆地植物的祖先。在这个项目中，来自CGA的一个模式生物，Penium margaritaceum，被用来研究果胶分泌的定量方面，亚细胞成分在果胶和细胞壁加工中的特定作用，以及关键的果胶修饰酶的作用。该项目应用各种实验、显微镜和免疫标记技术来研究内膜系统、细胞骨架/细胞分裂网络和细胞表面现象，这些现象复杂地涉及果胶向细胞壁的分泌。该项目的结果将被合成并用于构建植物中果胶动态的模型，并将为绿色植物细胞处理细胞壁聚合物、多个亚细胞系统在特定分泌活动中的协调相互作用以及原始绿色植物的进化提供洞察。该项目将为斯基德莫尔学院的4名本科生提供暑期研究机会，为6-10名本科生提供学期研究机会。该项目还将促进教育研究的整合，因为该项目的组成部分将用于加强植物生物学、植物生理学和生物电子显微镜等课程的教学和支持实验室经验。该项目还包括为大学预科学生提供的外展体验。具体地说，外展计划包括派和斯基德莫尔生物专业的学生向小学生及其老师介绍微观世界的一系列积极演讲。此外，PI和他的学生将于周六带领高中生和他们的老师前往湿地进行实地考察。实地考察将包括收集显微镜标本的活动，然后用显微镜进行鉴定。这项研究的结果将通过学生/PI报告和出版物、推广计划以及最近在斯基德莫尔学院建立的CGA网站广泛传播。

Intellectual Merit Cell wall polymers are important biochemicals in the growth, development and survival of green plants and constitute the most abundant biochemicals on the planet. Pectins represent one of the major classes of cell wall polymers and function in regulating cell wall expansion and cell growth as well as cell wall porosity and uptake of key ions. The synthesis, secretion and post-secretory remodeling of pectins represent key subcellular events in the life of a plant cell and specific studies to elucidate these processes have only just begun. Pectins are found in all land plant groups and have been recently characterized in the Charophycean Green Algae (CGA). The CGA represent the extant group of green algae that is ancestral to modern-day land plants. In this project, a model organism from the CGA, Penium margaritaceum, is employed to study quantitative aspects of pectin secretion, the specific role of subcellular components in pectin and cell wall processing, and the role of a key pectin-modifying enzyme. This project applies various experimental, microscopy-based and immunolabeling technologies to studies of the endomembrane system, cytoskeletal/cytomotile networks, and cell surface phenomena that are intricately involved in the secretion of pectins to the cell wall. The results of this project will be synthesized and used in the construction of models of pectin dynamics in plants and will provide insight into cell wall polymer processing by green plant cells, the coordinated interaction of multiple subcellular systems in defined secretory activities, and the evolution of primitive green plants. Broader Impacts This RUI project will provide summer research opportunities for 4 undergraduates and semester-based research opportunities for 6-10 undergraduates at Skidmore College. The project also will promote the integration of research in education as components of the project will be used to enhance instruction and support laboratory experiences in courses as Plant Biology, Plant Physiology, and Biological Electron Microscopy. The project also includes outreach experiences for pre-college students. Specifically the outreach plan includes a series of active presentations by the PI and Skidmore biology majors to elementary students and their teachers on the microscopic world. In addition the PI and his students will lead Saturday field trips to wetlands for high school and middle school students and their teachers. The field trips will include activities in collecting microscopic specimen followed by identification exercises with the microscope. The results of the study will be broadly disseminated through student/PI presentations and publications, outreach programs, and the recently established CGA website at Skidmore College.