大葱AfUFGT2基因的克隆及干旱胁迫下的表达分析

Cloning and Expression Analysis of AfUFGT2 in Welsh onion(Allium fistulosum L.)under Drought Stress

黄酮类化合物在植物抵抗非生物胁迫中起到重要作用,而糖基化修饰是黄酮类化合物代谢过程中的重要步骤,对植物黄酮类化合物的代谢具有重要意义。为解析大葱中类黄酮糖基化修饰的关键基因对干旱胁迫的响应,从大葱中分离到UFGT基因,并命名为AfUFGT2。生物信息学分析结果表明,AfUFGT2基因的编码序列长度为1353 bp,编码450个氨基酸,分子质量为48.08 ku,具有完整的糖基转移酶结构域。AfUFGT2编码蛋白为亲水性蛋白,无信号肽。氨基酸序列多重比较分析结果显示,在多个物种中UFGT都具有一定保守性。进化分析表明,AfUFGT2与AcUFGT1亲缘关系最近,同属类黄酮3-O-糖基转移酶分支,表明AfUFGT2负责大葱黄酮类化合物的3-O-糖基化修饰。亚细胞定位预测结果表明,AfUFGT2编码蛋白可能定位于细胞质中。实时荧光定量PCR结果表明,干旱胁迫处理能够促进AfUFGT2基因的表达,表明AfUFGT2基因可以响应干旱胁迫,暗示干旱胁迫下大葱可以通过提高AfUFGT2的表达,从而促进类黄酮化合物的生物合成,进而增强植物的抗旱性。

Flavonoids play an important role in plant resistance to abiotic stress.Glycosylation modification is an important step in the process of flavonoid metabolism,which is of great significance for plant flavonoid metabolism.In order to analyze the response of key genes involved in flavonoid glycosylation modification in Welsh onion to drought stress,in this study,UFGT gene was isolated from Welsh onion and named AfUFGT2.Bioinformatics analysis showed that the coding sequence of AfUFGT2 gene was 1353 bp in length,encoding 450 amino acids,with a relative molecular weight of 48.08 ku,and had a complete glycosyltransferase domain.AfUFGT2 protein was hydrophilic protein without signal peptide.Multiple comparative analysis of amino acid sequences showed that UFGT was conservative in many species.Evolutionary analysis showed that AfUFGT2 was the closest relative to AcUFGT1,belonging to the branch of flavonoid 3-O-glycosyltransferase,which indicated that AfUFGT2 was responsible for the 3-O-glycosylation modification of flavonoids in Welsh onion.The prediction results of subcellular localization indicated that AfUFGT2-encoded protein might be localized in cytoplasm.The real time fluorescent quantitative PCR showed that drought stress treatment could promote the expression of AfUFGT2 gene,which indicated that AfUFGT2 was able to respond to drought stress,suggesting under drought stress the biosynthesis of flavonoids was promoted in Welsh onion,and then the drought resistance of plants was enhanced.