Cellulose synthesis and regulation in plants.

植物细胞壁是一种复杂的动态结构，在植物的生长发育过程中起着重要的作用。如果不在植物细胞壁的背景下考虑植物细胞或组成植物的细胞的提纲，是不可能的。因此，要更好地了解植物是如何发育和生长的，就需要了解控制细胞壁组装和完整性的机制。尽管细胞壁由许多不同的糖聚合物组成，但主要的承载聚合物是纤维素。尽管纤维素含量丰富，经过多年的研究，但我们对纤维素是如何制造并整合到不断生长的墙体中的知识仍然非常有限。我的研究计划的主要目的是解决纤维素是如何合成的，以及这个过程是如何调节的。为了确定纤维素生物合成的机制，我们利用了两个模型系统：细菌，木糖乙酸葡糖杆菌和植物，拟南芥。细菌系统的优点是，在体外可以很容易地测量纤维素合成酶的活性，而到目前为止，这一点在植物中是很难测量的。而拟南芥可以进行遗传分析，这使我们能够从遗传上剖析植物中的纤维素生物合成。这两个系统将被用来实现三个短期目标：(1)确定纤维素合成酶蛋白质的结构-功能关系；(2)分析纤维素合成酶复合体结构；(3)识别潜在的纤维素合成酶调控因子。结合遗传分析，我们将使用现代细胞生物学和生化技术来试验性地实现这些目标。更深入地了解纤维素的生物合成将为理解自然界中有多长的链聚合物提供基础。此外，这一知识还可应用于天然聚合物的合成或改性。纤维素的特性，如微纤丝角，会影响木材质量、聚合度(葡萄糖单元的数量)和结晶度，这些都是经济利益所在。

The cell wall of plants is a complex and dynamic structure with many important roles in plant growth and development. It is impossible to consider a plant cell or the compendium of cells that make up a plant, if not in the context of their cell walls. Gaining a better understanding of how plants develop and grow therefore requires a knowledge of the mechanisms that control both cell wall assembly and integrity. Although the cell wall is made up of many different sugar polymers, the primary load-bearing polymer is cellulose. Despite its abundance and a number years of study, our knowledge of how cellulose is made and integrated into the growing wall is still very limited. The principle aims of my research program are to address how cellulose is synthesized and how this process is regulated. To determine the mechanisms of cellulose biosynthesis we are utilizing two model systems: a bacterium, Gluconoacetobacter xylinus, and a plant, Arabidopsis. The bacterial system has the advantage that cellulose synthase activity can be easily measured in vitro, something that has, so far, been difficult in plants. While Arabidopsis is amenable to genetic analysis, which allows us to genetically dissect cellulose biosynthesis in a plant. These two systems will be used to achieve three short-term objectives: (1) determine the structure-function relationships of cellulose synthase proteins, (2) analyze cellulose synthase complex structure and (3) identify potential cellulose synthase regulators. In combination with genetic analysis we will use modern cell biological and biochemical techniques to experimentally reach these goals. A deeper understanding of cellulose biosynthesis will provide the basis for understanding how long chain polymers are made in nature. In addition, this knowledge can be applied to creating or modifying natural polymers. Features of cellulose such as microfibril angle, which affects wood quality, the degree of polymerization (number of glucose units), and it’s crystallinity are all of economic interest.