旱麦草LEA3基因的克隆与序列分析

为了克隆旱麦草LEA3基因,根据小麦的LEA3基因(GenBank登录号为AY148492)cDNA序列设计引物,以干旱胁迫处理的旱麦草幼苗的cDNA为模板,采用RT-PCR克隆了旱麦草LEA3基因,命名为EtLEA3(GenBank登录号为KJ123698),并对基因及其蛋白进行了生物信息学分析。结果表明:EtLEA3基因的ORF全长为600 bp,编码199个氨基酸,推测的蛋白相对分子量为20.38 ku,理论等电点为9.08。其氨基酸序列与小麦、大麦和山羊草LEA3蛋白的相似性分别为83%、82%和81%。信息学分析表明EtLEA3蛋白具有较高的亲水性,没有跨膜结构。蛋白质二级结构和三级结构预测表明α-螺旋结构占主导,与目前已知的多种植物的LEA3蛋白具有相似的结构功能域。该蛋白含有5个完整的11个氨基酸组成的串联重复单元。这些特征均与第3组LEA蛋白的特征相符合。该研究结果为深入了解该基因的功能和旱麦草抗旱的分子机理提供了基础数据。

Cloning and Bioinformatics Analysis of LEA3 Gene from Eremopyrum triticeum

To clone LEA3 gene from Eremopyrum triticeum,a pair of primers were designed according to the LEA3 cDNA sequence from Triticum aestivum.A LEA3 cDNA fragment was obtained by RT-PCR from leaves of E.triticeum seedling under drought stress,and this gene was named as EtLEA3（GenBank accession number KJ123698）.EtLEA3 protein was also predicted and studied through the bioinformatics analysis method. The results showed that the open reading frame（ORF） of EtLEA3 gene was 600 bp and encoded a polypeptide of 199 amino acid residues.The estimated molecular weight and isoelectric point of the putative protein were 20.38 ku and 9.08,respectively.The amino acid sequence of EtLEA3 showed a similarity of 83%,82%and 81% with wheat,barley and Aegilops tauschii LEA3 homologs,respectively.The EtLEA3 protein was highly hydrophilic and without any transmembrane domain.The secondary and tertiary structure of EtLEA3 protein exhibited a quantity of α-helix dominant structures,which were similar to LEA3 homolog found in many other plant species.11-mer repeat units were found in EtLEA3 amino acid sequences.All these characteristics indicated that EtLEA3 belonged to group 3 LEA protein family.This research provided basic data for understanding the gene function further and molecular mechanism for drought-resistant in E.triticeum.