Functional Genomics of Hemicellulose Biosynthesis

随着植物基因组学的快速发展，植物基因组学的主要挑战将转移到分析基因及其编码的蛋白质的功能。这项任务对于许多基因来说尤其具有挑战性，这些基因的功能无法根据与其他生物中已知功能基因的序列相似性来预测。毫无疑问，这个问题在植物独特的领域，例如植物细胞壁的生物合成中将最为明显。虽然其他生物如细菌和酵母也有细胞壁，但它们的细胞壁在组成、结构和功能上与植物细胞有着根本的不同，因此在这些系统中学到的东西并不容易转移到植物的研究中。生物化学方法在鉴定与细胞壁生物合成相关的组分方面基本上不成功。然而，基因组方法非常适合于解决负责半纤维素生物合成的植物基因的鉴定和功能表征的问题。有几种策略可用于鉴定其产物参与细胞壁生物合成的基因，并用于发展关于其生化功能的可验证的假说。该奖项将支持在一个代表性的双子叶和单子叶植物细胞壁生物合成的分析。 这种比较研究是合理的，因为来自这些不同植物群的半纤维素在结构上是不同的。 双子叶植物将是拟南芥，这是用于实验的杰出的双子叶植物模型，单子叶植物将是玉米，这也是用于遗传、生物化学和基因组研究的优秀植物。具体目标是：（1）确定细胞壁生物合成酶的候选基因;（2）分析可能参与半纤维素生物合成的候选基因;（3）研究特定基因的功能。该奖项将支持植物半纤维素生物合成的综合分析，将整合各种现代生物学方法和概念，包括生物信息学，多糖生物化学，细胞和分子生物学以及遗传学。

With rapid progress in obtaining gene sequences for several plant species, the major challenge in plant genomics will shift to analysis of the functions of genes and the proteins they encode. This task will be especially challenging for the numerous genes whose function cannot be predicted based on sequence similarity to genes of known function in other organisms. Undoubtedly, this problem will be most obvious in areas where plants are unique, for example, in plant cell wall biosynthesis. Although other organisms such as bacteria and yeast have cell walls, their walls are fundamentally different in composition, structure, and function from those of plant cells, and therefore what is learned in those systems is not readily transferable to the study of plants. Biochemical approaches have been largely unsuccessful in identifying the components associated with cell wall biosynthesis. However, genomic approaches are well suited to addressing the problems of identification and functional characterization of plant genes responsible for hemicellulose biosynthesis. Several strategies are available for identifying the genes whose products are putatively involved in cell wall biosynthesis and for developing testable hypotheses regarding their biochemical function. This award will support the analysis of a cell wall biosynthesis in a representative dicotyledonous and monocotyledonous plant. Such a comparative study is justified because hemicelluloses from these different groups of plants are structurally distinct. The dicot will be Arabidopsis, the preeminent model dicot for experimentation, and the monocot will be maize, also an excellent plant for genetic, biochemical, and genomic research. The specific objectives are to: (1) identify candidate genes for cell wall biosynthetic enzymes; (2) analyze candidate genes for possible involvement in hemicellulose biosynthesis; and (3) investigate the function of specific genes. The award will support a comprehensive analysis of hemicellulose biosynthesis in plants that will integrate a variety of modern biological methods and concepts, including bioinformatics, polysaccharide biochemistry, cell and molecular biology, and genetics.