小麦Antiquitin cDNA克隆、空间结构预测及表达谱分析

cDNA Cloning,Structure Prediction and Expression Pattern Analysis of Antiquitin in Wheat(Triticum aestivum L.)

【目的】从普通小麦中克隆Antiquitin(TaATQ)cDNA,分析其编码序列及空间结构特征,研究其在不同组织、种子发育过程及干旱和盐胁迫下的表达谱。【方法】基于EST拼接,通过RT-PCR方法克隆小麦TaATQ cDNA;通过同源建模分析TaATQ的结构特征,通过实时定量PCR研究其在不同组织和胁迫条件下的表达谱。【结果】克隆到小麦TaATQ cDNA序列1 530 bp,编码54 kD目标蛋白。TaATQ属于醛脱氢酶超家族第7家族(ALDH7),与水稻、豌豆、人、小鼠、线虫、果蝇等物种ATQ序列相似性依次为91.7%、78.1%、58.3%、58.9%、58.1%和52.5%。细胞中,功能性TaATQ可能以四聚体形式存在,每个单体由NAD+结合结构域、催化结构域、寡聚化结构域3部分构成。盐胁迫条件下叶和根中TaATQ的表达均显著升高;干旱胁迫条件下,叶中TaATQ表达显著上升,而根中TaATQ表达变化不显著。【结论】TaATQ具备醛脱氢酶家族蛋白典型结构特征,在小麦抗逆过程中起重要作用,可作为提高作物抗旱耐盐的靶基因应用于作物遗传改良。

【Objective】The cDNA of Antiquitin（TaATQ） was cloned from wheat（Triticum aestivum L.）,the sequence and structure features of its encoded protein were analyzed,and the expression levels were evaluated.【Method】Based on EST assembling,the cDNA of TaATQ was cloned by RT-PCR.The structure features was analyzed by homology modeling.The expression patterns of the gene in different tissues,during seeds development and under different stress,were investigated using quantitative real-time PCR（qRT-PCR）.【Result】The cDNA includes 1 530 bp complete CDS and encodes a 54 kD protein.TaATQ belongs to the 7th family of aldehyde dehydrogenase super family,it shows 91.7%,78.1%,58.1%,58.3% and 58.9% identity with Antiquitin of rice,garden pea,nematode,human and mouse respectively.Functional TaATQ may form a tetramer in cell,and each monomer is composed of three typical domains,a NAD＋-binding domain,a catalytic domain and an oligomerization domain.The expression levels of TaATQ in both leaf and root were increased significantly during the application of high salt.Under drought stress,the transcripts of TaATQ was elevated only in leaf.【Conclusion】TaATQ has typical structure features of ALDH protein family,it plays an important role during the process of stress response.TaATQ can be used as a target gene for crop genetic improvement.