Collaborative Research:RUI: Invasion of land: Using model charophyte Penium margaritaceum to elucidate subcellular responses to stress that were key in the evolution of land plants

4.5亿至5亿年前绿藻在陆地上的殖民和它们进化成陆地植物是地球自然史上的重要事件。这些陆生植物对地球的生物化学和生物圈造成了重大的变化。陆地植物是从绿藻进化而来的，绿藻是一种小而多样的淡水和陆地生物。绿藻在陆地上成功定植的关键是细胞外基质（ECM）。这种ECM由覆盖细胞外部的细胞壁和这些生物体分泌的凝胶状物质组成。该项目将提供一个全面的了解的形成和ECM的charophyte被测试，Penium的功能。这种生物将在各种环境条件下生长，包括缺水和极度干燥。ECM及其相关的生物合成过程将使用由美国国家科学基金会资助的尖端技术进行研究。这项研究将深入了解古代蕨类植物在陆地上开始生存的重要机制，以及今天许多陆地植物仍在使用的机制。这些信息将用于设计植物如何适应陆地生活以及它们如何忍受干旱等非生物压力的模型。该项目还将提供博士后培训和暑期本科生研究的机会，为当地高中生开展外部暑期项目，并为未来的课程发展奠定基础。本项目的目的是提供一个全面的了解细胞外基质（ECM）及其生物合成动力学在模式蕨草，Penium。它将检查发生在ECM处理的变化，当细胞处于干燥压力下。ECM及其生物合成机器将使用分子、生化和高分辨率显微镜技术进行研究，这些技术先前由美国国家科学基金会资助。这将使我们深入了解古代蕨类植物在陆地上生存的重要机制，并继续被许多陆地植物所利用，包括那些遭受干旱的植物。需要研究的具体领域包括：(A) Penium中极性细胞的生长，重点是壁膨胀过程中果胶和纤维素的产生；(B) ECM成分的分泌涉及两种不同的途径，细胞壁多糖与胞外聚合物（EPS）一起传递到特定的扩张区，并靶向暂时性分泌部位；(C)细胞壁结构改变；(D) EPS的目标生产和输送对耐受非生物胁迫至关重要。本项目的研究成果对植物进化生物学、细胞生物学、分子生物学和发育生物学等领域具有重要意义。该项目还将为外展和学生培训提供重要机会。

The colonization of land by green algae 450 to 500 million years ago and their evolution into land plants represent important events in the natural history of the planet. These terrestrial (land) plants have caused major changes to the Earth's biochemistry and biosphere. Land plants evolved from green algae called charophytes, a small but diverse group of freshwater and terrestrial organisms. Central to the success of the charophyte colonization of land was the extracellular matrix (ECM) that surrounds their cells. This ECM is made up of a wall that covers the outside of the cell and the gel-like substances that are secreted from these organisms. This project will provide a comprehensive understanding of the formation and function of the ECM of the charophyte being tested, Penium. This organism will be grown under various environmental conditions, including water stress and extreme dryness. The ECM and its related biosynthetic processes will be studied using cutting edge technologies that were previously funded by the National Science Foundation. This research will provide insight into the mechanisms that were important to initiate survival on land by ancient charophytes, as well as mechanisms that are still used by many land plants today. This information will be used to devise models of how plants adapt to life on land and how they tolerate non-biological stresses such as drought. This project will also provide opportunities for post-doctoral training and summer undergraduate research, initiate external summer programs for local high school students, and serve as a basis for future course development.The goal of this project is to provide a comprehensive understanding of the extracellular matrix (ECM) and its biosynthesis dynamics in the model charophyte, Penium. It will examine the changes that occur in ECM processing when cells are placed under desiccation stress. The ECM and its biosynthetic machinery will be studied using molecular, biochemical, and high resolution microscopy technologies previously funded by the National Science Foundation. This will provide insight into mechanisms that were important to survival on land by ancient charophytes and continue to be used by many land plants, including those exposed to drought. Specific areas to be studied include: (A) polar cell growth in Penium, with an emphasis on pectin and cellulose production during wall expansion; (B) the secretion of ECM components involving two distinct pathways, the cell wall polysaccharides delivered to specific expansion zones along with extracellular polymeric substances extracellular (EPS) targeted to transitory secretion sites; (C) changes in cell wall architecture; and (D) EPS targeted production and delivery that are critical for tolerating abiotic stresses. The results of this project will be of significance to the fields of plant evolutionary biology, cell biology, molecular biology, and developmental biology. This project will also provide significant opportunities for outreach and student training.