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为了从分子水平上研究棉铃虫Helicoverpa armigera(Hbner)对杀虫剂抗性的产生机理,本文通过RT-PCR和 RACE方法首次从棉铃虫中肠中克隆了一个羧酸酯酶全长cDNA序列。序列分析表明,该基因包含一个1 794 bp的开放读码框,129 bp的5’UTR和139 bp的3’UTR区域。该基因编码597个氨基酸,推测编码蛋白质的等电点pI为 4.92,分子量为67.1 kD,GenBank登录号为EF547544。通过对氨基酸的同源性分析表明,该羧酸酯酶与斜纹夜蛾 Spodopteralitura羧酸酯酶的同源性最高,达60 %。半定量RT-PCR分析表明,该基因在中肠组织中表达量最高,在脂肪体和生殖腺中表达量较低,在头部则不表达。推测该羧酸酯酶基因可能主要参与棉铃虫对外源物质的解毒代谢。
In order to study the mechanism of insecticide resistance of Helicoverpa armigera (Hbner) at the molecular level, a carboxylesterase full-length cDNA was cloned from cotton midgut for the first time by RT-PCR and RACE sequence. Sequence analysis showed that the gene contains a 1 794 bp open reading frame, 129 bp 5’UTR and 139 bp 3 ’UTR region. The gene encoding 597 amino acids, suggesting that the protein encoded pI was 4.92, the molecular weight of 67.1 kD, GenBank accession number EF547544. The amino acid homology analysis indicated that the carboxylesterase had the highest homology with Spodopteralitura carboxylesterase (60%). Semi-quantitative RT-PCR analysis showed that the gene was expressed highest in midgut tissue, lower in fat body and gonad, but not in head. It is speculated that the carboxylesterase gene may be mainly involved in the detoxification metabolism of the exogenous substances of cotton bollworm.