Arabidopsis Seed Coats as a Model System for Molecular Genetic Analysis of Plant Cell Wall Biosynthesis and Modification

植物细胞壁通常由多糖纤维素和半纤维素组成，包埋在称为果胶的亲水性碳水化合物凝胶中。这些细胞壁成分相互作用，形成一个环境屏障，满足细胞在生长和分化过程中的需要。此外，细胞壁提供细胞外基质，相邻细胞通过细胞外基质彼此连接。因此，关于植物细胞壁结构以及细胞如何随着细胞发育和适应变化的环境而改变的信息是有价值的，并且在农业和林业中有许多应用。我们研究了一种专门的细胞类型的拟南芥种皮，使大量的细胞壁多糖。鉴定不能正确合成这些多糖的突变体，并用于分离编码细胞壁生物合成和修饰所需蛋白质的相应基因。这些基因及其蛋白质产物可以作为了解细胞壁结构和功能的工具。使用这种方法，我们建议研究如何：1。多糖可以被修饰以使细胞壁或多或少地具有粘性，2.细胞将蛋白质靶向细胞壁，3.细胞壁特性需要特定的细胞壁碳水化合物，4.细胞壁蛋白质降解，5。细胞壁是在分子水平上构造的。我们相信这些问题的答案将有助于我们理解和操纵细胞壁的物理性质，以影响植物的生长和发育。

Plant cell walls are typically composed of the polysaccharides cellulose and hemicellulose, embedded in a hydrophilic, carbohydrate gel called pectin. These cell wall components interact with one another to create an environmental barrier that meets the needs of the cell during growth and differentiation. In addition the wall provides an extracellular matrix through which adjacent cells are connected to each other. Consequently, information concerning plant cell wall structure and how it can be modified as cells develop and adapt to a changing environment is valuable and has many applications in agriculture and forestry. We study a specialized cell type of the Arabidopsis thaliana seed coat that makes large quantities of cell wall polysaccharides. Mutants unable to synthesize these polysaccharides correctly are identified and used to isolate the corresponding genes encoding proteins needed for cell wall biosynthesis and modification. These genes and their protein products can then be used as tools to understand cell wall structure and function. Using this approach we propose to study how: 1. polysaccharides can be modified to make the cell wall more or less cohesive, 2. cells target proteins to the cell wall, 3. specific cell-wall carbohydrates are required for cell wall properties, 4. Cell wall proteins are degraded, and 5. the cell wall is structured at the molecular level. We believe that answers to these questions will help us to understand and manipulate physical properties of the cell wall for the purposes of influencing plant growth and development.