苦荞蔗糖合酶基因克隆及序列分析

Cloning and Sequence Analysis of Sucrose Synthase Gene(SuSy) from Fagopyrum tataricum

以苦荞基因组DNA为模板，根据已构建的苦荞eDNA文库中蔗糖合酶（Sucrose synthase，SuSy）的部分eDNA序列设计引物，PCR扩增SuSy基因的核心片段，结合Genomic walking技术获得SuSy基因的完整序列。生物信息学分析表明，该基因序列全长4428bp，含有12个外显子和11个内含子，剪接位点均符合经典GU—AG法则，ORF长度为2412bp，共编码803个氨基酸。其氨基酸序列与籽粒苋（Amaranthus hypo—chondriacus）、甜菜（Beta vulgaris）、红叶藜（Chenopodium rubrumL）和大豆（Glycine max）的相似性分别为86％、86％、85％和83％。保守结构域分析表明，SuSy含有1个GT1糖基化酶功能结构域（275～760）和4个ADP结合位点，能够催化果糖-6-磷酸和尿苷5L二磷酸葡萄糖形成蔗糖-6-磷酸。

We designed the primers according to the cDNA sequence of the sucrose synthase gene （Su- Sy） obtained from cDNA library of buckwheat in laboratory. The core fragment of the sucrose synthase gene （SuSy） was amplified by PCR and a fullqength DNA sequence was cloned by Genomic Walking. Bioinformatics analysis showed that the full-length of SuSy gene of Fagopyrum tatarium was 4 428 bp including 11 introns and 12 exons. The ORF of SuSy gene was 2 412 bp,probably encoding a protein of 803 amino acids. Further analysis indicated that the deduced SuSy protein had homology of 86 %,86 %,0,85 % and 83 % with Amaranthus hyDochondriacus, Beta vulgaris, ChenoDodiurn rubrum L,Glycine rnaz. Protein conserved domain searching results showed that SuSy contained a GT1 sucrose synthase domain and four putative ADP-binding pockets which may catalyze the synthesis of sucrose 6-phosphate from fructose 6-phosphate and uridine 5P-diphosphate-glucose. This result laid the foundation for further exploration of the expression regulation of sucrose synthase in tartary buckwheat.