Diversification and Functional Specialization of Cellulose Synthase

纤维素微原纤维为植物细胞壁提供强度，也为许多由木材和其他植物纤维制成的商业产品提供强度。虽然纤维素在许多应用中提供了理想的强度和耐久性，但生物燃料工业将受益于更容易受到酶或化学分解的纤维素供应。纤维素微原纤维的结构和物理性质是通过生物合成过程产生的，因此可以进行潜在的修饰。纤维素是由膜复合物（CSCs）合成的，在种子植物中，CSCs由24-36个三种不同类型的纤维素合成酶亚基组成，排列成玫瑰状。藻类和植物的比较研究已经证明了CSC形状与纤维素微纤维结构之间的关系。然而，决定CSC形状的因素是未知的。模式苔藓类小立藓（Physcomitrella patens）的CSCs具有与维管植物类似的玫瑰花状结构，但在亚基组成上与种子植物的CSCs不同。研究人员将使用生化、遗传和分子方法来确定小立碗藻CSCs的亚基组成，并测试有关其进化起源的特定假设。通过澄清纤维素合酶的进化史，本研究的结果将指导人们努力确定每种不同类型的纤维素合酶对种子植物csc的组装和功能的贡献。该项目的更广泛影响包括培训研究生和本科生，包括来自代表性不足群体的学生；开发面向初高中学生的学习模块，重点是分析和解释研究生和本科生生成的数据；以及对纤维素生物合成机制的基本认识的产生，可能有助于在商业植物中基因操纵纤维素生物合成的努力。

Cellulose microfibrils provide strength to plant cell walls, as well as to the numerous commercial products made from wood and other plant fibers. Whereas cellulose provides desirable strength and durability in many applications, the biofuel industry would benefit from a supply of cellulose that is more susceptible to enzymatic or chemical breakdown. The structure and physical properties of cellulose microfibrils arise through the biosynthetic process and thus can potentially be modified. Cellulose is synthesized by membrane complexes (CSCs) that, in seed plants, consist of 24-36 cellulose synthase subunits of three different types arranged in a rosette shape. Comparative studies of algae and plants have demonstrated a relationship between CSC shape and cellulose microfibril structure. However, the factors that determine CSC shape are unknown. The CSCs of the model moss species, Physcomitrella patens, have a rosette shape like those of vascular plants, but they differ from seed plant CSCs in subunit composition. The investigators will use biochemical, genetic and molecular approaches to determine the subunit composition of the Physcomitrella patens CSCs and test specific hypotheses pertaining to their evolutionary origin. By clarifying the evolutionary history of cellulose synthase, the results of this investigation will guide efforts to determine the contributions of each of the distinct cellulose synthase types to the assembly and function of seed plant CSCs. The broader impacts of this project include training of graduate and undergraduate students, including those from underrepresented groups; development of learning modules for middle and high school students focusing on analysis and interpretation of data generated by graduate and undergraduate students; and generation of fundamental knowledge about the mechanism of cellulose biosynthesis that may contribute to efforts to genetically manipulate cellulose biosynthesis in commercial plants.