干旱胁迫下小麦葡萄糖-6-磷酸脱氢酶基因TaG6PDH1的表达特征及启动子分析

Promoter Analysis and Characterization of a Glucose-6-phosphate Dehydrogenase Gene TaG6PDH1 of Wheat during Drought Stress

为进一步揭示小麦抗旱性的生物学机理,通过电子克隆和RT-PCR方法,在水源11小麦叶片中分离得到1个新的小麦葡萄糖-6-磷酸脱氢酶基因TaG6PDH1后进行基因序列特征和启动子元件组成分析,并利用实时荧光定量PCR(Quantitative real-time PCR,qRT-PCR)技术对其在PEG模拟干旱胁迫下的表达特征进行分析。结果表明,TaG6PDH1基因的cDNA全长1 338bp,编码445个氨基酸。TaG6PDH1蛋白具有典型的G6DPH结构,即C-端葡萄糖-6-磷酸结合激活序列、N-端NAD(P)结合位点和C-端保守的Cys位点。系统进化分析表明,TaG6PDH1蛋白与质体型G6PDH中的P2型相似性较高,其与OsG6PDH5有极高的同源性。启动子区域分析表明,所选区域包含核心启动子和上游应答元件,该区域为TaG6PDH1基因转录的启动子区域,在该区域存在的顺式作用元件有ERF1与HMG-I/Y等,在调控植物防卫反应中有重要的生物学意义。qRT-PCR分析表明,TaG6PDH1基因在PEG模拟干旱胁迫下从6h开始被上调,48h被上调最大,说明TaG6PDH1基因参与了小麦干旱应答防卫反应,其可能作为一种正调控因子参与到小麦的防卫反应信号途径中。

In order to make a foundation for revealing the biological mechanism of drought resistance in wheat,a glucose-6-phosphate dehydrogenase gene, TaG6PDH1, was cloned from the wheat ＂Su 11＂ leaves using in silico cloning and RT-PCR. The ORF and promoter of TaG6PDH1 gene was analyzed by bioinformatics methods,and its expression pattern was analyzed through qRT-PCR under drought stress imitated by PEG in this research. The full length cDNA of TaG6PDH1 gene was 1 338 bp, which encodes 445 amino acids. Analysis of the functional domain features indicated that TaG6PDH1 protein contains typical conserved structures, including C-terminal active site, N-terminal NAD （Pi binding site and C-terminal conserved Cys site. Phylogenetic analysis of G6PDHs demonstrated that TaG6PDH1 protein clusters with P2-G6PDH, which was classified into plastidic G6PDH, and shared high homology with OsG6PDHS. The prediction and analysis of promoter region showed that it contained the core promoter sequence and the upstream response element, which was the promoter se- quence of TaG6PDH1 gene. And the cis-acting elements,such as,ERF1,AG, HMG-I/Y,were pre- dicted in this promoter structure. Transcriptional analysis of TaG6PDH1 gene suggested that TaG6 PDH1 gene was highly induced by drought. The expression level increased at 6 h,and hit the peak at 48 h under PEG treatment. The results Suggested that TaG6PDH1 gene was involved in the wheat defense response to drought stress and probably played a role in the reaction signal pathway.