萱草糖转运蛋白HfSWEET2a的克隆及低温胁迫下的表达分析

Cloning and Expression Analysis of a Hemerocallis Fulva HfSWEET2a and Its Expression under Low Temperature Stress

萱草是我国传统花卉中久负盛名的宿根花卉,广泛用于家庭园艺、园林绿化等领域。糖是植物光合作用的主要产物,也是植物体内的主要能源物质,SWEET蛋白是近年发现的一种糖外排转运蛋白,参与植物生殖发育、衰老和逆境响应等生理过程。采用同源克隆法从萱草叶片中克隆了萱草SWEET2a基因,命名为HfSWEET2a(GenBank登录号为MT379659),进行了序列分析、同源蛋白序列比对以及系统进化树分析,研究了其在不同温度下的表达量。序列分析结果表明,HfSWEET2a基因包括包含1个690 bp的完整开放阅读框,编码229个氨基酸。理化性质分析结果表明HfSWEET2a蛋白分子量25.531 kDa,等电点9.16。亚细胞定位显示其定位在细胞膜。HfSWEET2a含有典型的7个跨膜结构。系统进化分析表明,HfSWEET2a编码的蛋白与芦笋的亲缘关系最近,其次是菠萝,相似性分别为75.58%、74.6%。HfSWEET2a基因在0℃下表达量最高,0℃相对表达量是15℃下的3.3倍、是10℃下的1.7倍、是5℃下的3.7倍,根据研究结果推测萱草HfSWEET2a基因参与了低温胁迫应答的响应。

Hemerocallis fulva is a well-known perennial flower in Chinese traditional flowers,which is widely used in family gardening,landscaping and other fields.Sugar is the main product of photosynthesis and the main energy source in plants.SWEET protein is a type of glycoefflux transporter found in recent years,which is involved in plant multiple physiological processes,including reproductive development,senescence and abiotic stress responses.In this study,Hemerocallis fulva SWEET2a gene was cloned from Hemerocallis fulva leaves by Quantitative Real-time PCR(qPCR),named HfSWEET2a(GenBank accession No.MT379659).Sequence analysis,homologous protein sequence alignment and phylogenetic tree analysis were carried out,and its expression at different temperatures was studied.The results of sequence analysis showed that HfSWEET2a gene contain a 690 bp ORF(open reading frame),encoding 229 amino acid residues.The results of physicochemical analysis showed that the molecular weight of HfSWEET2a is 25.531 kDa and the isoelectric point is 9.16.Subcellular localization showed that it is located in the Cell Membrane.HfSWEET2a has 7 typical transmembrane structures.The phylogenetic analysis of HfSWEET2a indicated that it has the closest relationship with asparagus,and pineapple was the second,with the similarity of 75.58%and 74.6%,respectively.The expression of HfSWEET2a gene was the highest at 0℃,the relative expression at 0℃was 3.3 times of that at 15℃,1.7 times of that at 10℃and 3.7 times of that at 5℃.According to the research results,it was speculated that the HfSWEET2a gene of Hemerocallis fulva participated in the response to low temperature stress.