烟夜蛾幼虫中肠Bt Cry1Ac毒素受体蛋白cDNA片段的克隆和序列测定

Molecular Cloning and Sequencing of cDNA Fragment Encoding Bt Cry1Ac Toxin Binding Protein from the Midgut of Helicoverpa assulta Guenée Larva

利用RT-PCR技术扩增烟夜蛾(HelicoverpaassultaGuen啨e)幼虫中肠Bt毒素Cry1Ac受体蛋白APN(N-氨基肽酶,aminopeptidaseN,APN)基因片段,克隆和测序结果表明,测序得到的812bp的片段编码270个氨基酸残基,且该片段在阅读框内。通过同源性分析发现,其核苷酸序列与棉铃虫(H.armigera)、澳洲棉铃虫(H.punctiger a)、烟芽夜蛾(H.virescens)、舞毒蛾(Lymantriadispar)、小菜蛾(Plutellaxylostella)、印度谷螟(Plodiainterpunctella)RC688品系和HD198品系、烟草天蛾(Manducasexta)和家蚕(Bombyxmori)的Cry1Ac受体蛋白基因的同源性分别为97.0%,90.0%,78.0%,63.5%,55.0%,60.3%,61.2%,55.0%和59.0%。推导的烟夜蛾Cry1Ac受体蛋白基因的氨基酸序列与棉铃虫、烟芽夜蛾、斑实夜蛾、舞毒蛾的氨基酸序列同源性分别为95.6%,81 0%,82 7%和55 7%。该片段编码的氨基酸属于氨肽酶家族,与烟夜蛾对BtCry1Ac毒素的抗性有关。

The cDNA fragment of Bt Cry1 Ac toxin binding protein from the midgut of Helicoverpa assulta larva was reamplificated using RT-PCR technique. This fragment was further cloned and sequenced. The sequenced result showed that the 812 bp nucleotide sequence that encods 270 amino acid residues were in the encoding frame. Compared with APN gene sequences of Helicoverpa armigera,Helicoverpa punctigera ,Heliothis virescens, Lymantria dispar,Plutella xylostella,Plodia interpunctella Rc688,Plodia interpunctella HD198,Manduca sexta and Bombyx mori, the identity were 97.0%,90.0%,78.0%,63.5%,55.0%,60.3%,61.2%,55.0% and 59.0% respectively .Compared with Bt Cry1Ac binding protein amino acid sequence of Helicoverpa armigera,Heliothis virescens, Helicoverpa punctigera, Lymantria dispar,the homology of the reduced amino acid sequence of Helicoverpa assulta APN the gene were 95.6%,81.0%,82.7% and 55.7% respectively. Moreover the encoding amino acid sequence belongs to the amniopeptidase N (APN) family which is associated with insect resistance to Bt.