植物果聚糖合成酶基因克隆及特性分析

Cloning and Characterization in Structure and Function of Fructan Biosynthesis Enzymes (FBEs) Gene in Plant

果聚糖(fructan)是蔗糖来源的果糖多聚体,其类型常因聚合度的多寡、分支结构有无、相邻果糖基成键差异及葡萄糖位置不同而多种多样。果聚糖不仅是植物储存非结构性碳水化合物的形式之一,而且在干旱、低温等非生物胁迫中具有保护植物细胞免受伤害的作用。果聚糖作为一种益生素,对人体健康具有保健作用,有效减少或避免结肠癌、心血管疾病及骨质疏松等发病机率。就果聚糖的存在形式、生物合成代谢途径、果聚糖合成酶(fructan biosynthetic enzymes,FBEs)基因克隆和转化等研究做一介绍,并对植物中FBEs结构特点进行了讨论,同时对小麦中FBEs基因的拷贝数、染色体定位及亚细胞定位等研究进行了讨论,为从更多植物中分离FBEs基因,研究FBEs基因的作用方式和表达特性,以及利用转基因技术提高重要作物抗逆性奠定基础。

Fructans are sucrose-originated polyfructoses, which can be divided into different kinds according to the difference of DP （ degree of polymerization） with or without branch structures, the binding type between the two adjacent fructosyls and the different sites of glucoses. Fructans play important roles not only as a source of carbohydrate, but also as agents protecting high plants against abiotic stresses such as water deficit and low temperature. Moreover, they are also utilized as probiotics in human diets, as low-calory sweeteners and are digested in the lower gut, resulting in the decreased incidence of colonic cancer, cardiovascular disease and osteoporosis. Some related studies on fructans including their presence, biosynthesis or degradation pathway, cloning and transformation of encoding genes were presente. At the same time, in-depth exploration on the copy number, chromosome assignment and sub-celluar localization of fructan biosynthesis enzyme genes （FBEs） were also taking. The sequence features of FBEs are also analyzed to further clone FBEs genes from more plants, study their function and expression pattern one by one, and improve abiotic stress tolerance and fructan accumulation in some important crops by gene engineering.