Production and stabilization of antioxidant compounds in genetically modified plants introduced engineered glucosyltransferases.

多酚化合物，如类黄酮类、硫氰素和儿茶素，起到了强大的抗氧化剂的作用，并防止由活性氧和/或其他氧化剂引起的疾病。这些抗氧化剂多酚是在植物中产生的对抗环境胁迫的物质，它们具有降低植物细胞中氧化应激的功能。提高多酚类化合物的产量和稳定性的转基因植物被认为具有更强的抗氧化剂和氧化胁迫能力，并能在空气污染地区存活。另一方面，将高抗氧化植物作为食品和药物资源，可以预防由氧化应激和环境氧化剂引起的人类疾病。花色苷在许多植物中普遍存在，并通过其分子中的糖基化作用稳定在植物细胞中。此外，花青素的产生受转录因子如Myc和Myb同源蛋白的协调调节。本课题研究了(1)利用植物葡萄糖转移酶基因工程重组蛋白改善花色苷的稳定性和溶解性，以及(2)在转基因植物中导入Myc或Myb同源蛋白对花色苷生产性能的影响。利用来自不同植物的几个葡萄糖转移酶克隆，研究了底物的特异性。在导入Myc和Myb同源物的转基因植株中，花青素的产量增加。利用酵母细胞中的一个/两个杂交系统，在体外研究了这些因子的反式激活功能。

Polyphenol compounds such as flavonoids, athocyanins and catecins act as strong antioxidants and prevent deseases occored by active oxygen and or other oxidants. These antioxidant polyphenols are produced in plant against environmental stresses and they have functions to reduce the oxidative stresses in plant cells. Genetically modified plants in which producibility and stability of polyphenol compounds increased are supposed to be more resistant against oxidants and oxydative stresses and can survive in arear of air pollution. On the other hand, taking high-antioxidant plants as food and medicinal resources might prevent human deseases that are induced by oxidative stresses and environmental oxidants. A group of anthocyanins are commonly produced in many plant species, and stabilized by glucosylation in their molecules in plant cells. Furthermore, anthocyanin production is coordinately regulated by transcriptional factors such as Myc and Myb homologue proteins. In this project, (1)the modification of stability and solubility of anthocyanins with engineered recombinant proteins of plant glucosyltransferases and(2)the modification of anthocyanin producibility in transgenic plant introduced Myc or Myb homologue proteins were investigated. Using several clones of glucosyltransferases from different plant species, substrate specificities were investigated. In transgenic plants introduced Myc and Myb omologues, productions of anthocyanin were increased. The details of transactivational functions of these factors were studied in vitro by using one/two hybrid systems in yeast cells.