甜菜夜蛾类钙粘蛋白基因全长cNDA的克隆及序列分析
Cloning and sequence analysis of the cadherinlike protein gene in beet armyworm, Spodoptera exigua
王玲 江幸福 罗礼智 胡毅 张蕾
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作者单位:中国农业科学院植物保护研究所 植物病虫害生物学国家重点实验室北京100193
中文关键词:甜菜夜蛾, 类钙粘蛋白, 基因克隆, 序列分析
英文关键词:Spodoptera exigua, cadherinlike protein, gene cloning, sequence analysisBt.
中文摘要: 昆虫中肠膜上的类钙粘蛋白(cadherinlike protein)是Bt毒素的一类重要受体,它与Bt毒素对昆虫的杀虫作用机制以及昆虫对Bt毒素的抗性等密切相关。本研究根据已报道的其它昆虫的类钙粘蛋白基因的保守区设计简并引物,应用RTPCR和RACE技术克隆了迁飞性重要害虫甜菜夜蛾Spodoptera exigua (Hübner)类钙粘蛋白基因全长cDNA序列(命名为SeCAD,GenBank登录号为 HQ647122),全长5 582 bp,编码1 739个氨基酸,推导的氨基酸序列包括1个信号肽、1个前蛋白区、11个钙粘蛋白重复、1个近膜区、1个跨膜区和1个胞质区。预测的分子量和等电点分别为196.447 ku和4.47。该蛋白与同科的大螟Sesamia inferens、蛀茎夜蛾S. nonagrioides、烟芽夜蛾Heliothis virescens、烟夜蛾Helicoverpa assulta亲缘关系更近,氨基酸序列一致性分别为61.28%、60.34%、60.14%、60.08%。这些结果对于揭示转Bt基因作物对非靶标、迁飞性甜菜夜蛾的杀虫作用机制以及评价其潜在的对Bt毒素抗性机制等奠定了基础。
英文摘要: The cadherinlike proteins, located in the brush border membrane vesicles (BBMV) of the insect midgut, are major receptors of Bacillus thuringiensis insecticidal crystal protein. The complete cDNA sequence of the cadherinlike protein gene in the beet armyworm, Spodoptera exigua (Hübner) was amplified using RTPCR and RACE techniques. The full cDNA sequence (named as SeCAD, GenBank accession no. HQ647122) is 5 582 bp in length, encoding 1 739 amino acid residues. The deduced amino acid sequence shows typical characteristics of the known insect cadherin proteins, including a signal peptide, a proprotein region, eleven cadherin repeats, a membraneproximal region, a transmembrane region and a cytoplasmic region. The predicted molecular weight and isoelectric point are 196.447 ku and 4.47, respectively. The cadherinlike protein from S. exigua shows a close relationship to cadherin proteins from Sesamia inferens, S. nonagrioides, Heliothis virescens and Helicoverpa assulta, with amino acid identity of 61.28%, 60.34%, 60.14% and 60.08%, respectively. These results can provide a basis for revealing the insecticidal mechanism of Bt in S. exigua, and the resistance mechanism of S. exigua to Bt.