Biosynthesis and Secretion of Plant Cell Walls

包裹每个植物细胞的细胞壁决定了它的形状，而细胞壁的多糖决定了细胞如何构建成组织、器官和整个植物。植物细胞壁是包括所有农业和林业在内的环境中植物生产的基础，本研究计划的长期目标是了解植物细胞如何合成和分泌其细胞壁前体，包括多糖和特殊的壁成分，如脂类和木质素。我们使用最先进的显微镜工具，如冷冻固定、高分辨率电子显微镜、电子断层扫描和活细胞成像来产生最高质量的细胞结构信息，并将其与使用分子生物学和生物化学的细胞成分的功能表征相结合。这项建议的短期目标是：1)阐明合成细胞壁多糖的酶是如何组织并保留在称为高尔基体的细胞膜堆叠中的；2)测试植物细胞可以通过独特的纳米空间(内质网和质膜之间15-30 nm的小间隙)将脂类运输到细胞壁的假说；3)确定木质部发育过程中木质素成分是如何输出到细胞壁的。随着细胞壁转化为独特的生物聚合物和乙醇生物燃料的潜力得到促进，细胞壁生物学领域变得极其活跃。这一基础研究计划的成果将是加强对植物细胞壁生物学的理解，这有可能为应用研究提供信息，以及培训年轻的细胞壁研究人员从事尖端基础生物学。

The cell wall encasing each plant cell determines its shape and the polysaccharides of the cell wall determine how cells are built into tissues, organs, and whole plants. Plant cell walls are the foundation of plant production in the environment, including all agriculture and forestry.The long-term goal of this research program is to understand how plant cells synthesize and secrete their cell wall precursors, both the polysaccharides and specialized wall components such as lipids and lignin. We use state of the art microscopy tools, such as cryo-fixation, high resolution electron microscopy, electron tomography, and live cell imaging to produce the highest quality cell structure information and combine this with functional characterization of cellular components using molecular biology and biochemistry.The short-term goals of this proposal are: 1) to elucidate how enzymes that synthesize cell wall polysaccharides are organized and retained inside the cell in membrane stacks called Golgi bodies; 2) to test the hypothesis that plant cells can transport lipids to the cell wall through unique nanospaces, small gaps of 15-30 nm, between the endoplasmic reticulum and the plasma membrane; and 3) to define how the components of lignin are exported into cell walls during xylem development. The field of cell wall biology has become extremely active as the potential for the conversion of cell walls into unique biopolymers and ethanolic biofuel has been promoted. The products of this fundamental research program will be an enhanced understanding of plant cell wall biology that has the potential to inform applied research as well as the training of young cell wall researchers in cutting-edge basic biology.