小菜蛾PxALP1基因的克隆与生物信息学分析

Cloning and Bioinformatic Analysis of PxALP1 Gene from Plutella xylostella

小菜蛾是一种世界性分布的重要农业害虫,也是最早对无公害生物农药Bt毒素产生抗性的种群之一。已有研究显示,在多种昆虫体内碱性磷酸酶是Bt毒素蛋白的直接受体,但在小菜蛾中,碱性磷酸酶的编码基因及其生物学功能尚极少有人研究。本研究克隆了小菜蛾PxALP1基因的开放阅读框(ORF),并推导出其氨基酸序列。经SMART网站分析,发现该蛋白质在第79~513位氨基酸残基区域存在典型的alk PPc(alkaline phosphatase homologues)结构域;经SWISS-MODEL同源模建预测蛋白质三级结构,发现该蛋白质具有典型的跨膜结构域,说明它是一个潜在的膜结合碱性磷酸酶。通过进化树分析,发现小菜蛾PxALP1与鳞翅目昆虫家蚕膜结合碱性磷酸酶的亲缘关系最近,BLAST比对发现PxALP1与家蚕Bm Alpm在氨基酸序列上的一致性(identity)为36.3%,相似性(similarity)为50.3%,说明二者之间具有较好的进化保守性。

The diamondback moth, Plutella xylostella （ L. ）, is one of the world wide agricultural pests of cruciferous vegetables, and is also one of the earliest populations which produce resistance to pollution -free biological pesticide Bt toxin. The membrane bound alkaline phosphatase has been shown to be a direct receptor of Bt toxin protein in many insects according to previous studies. However, the coding genes and biological functions of Plutella xylosteUa alkaline phosphatase is rarely known. In this study, the open reading frame （ORF） of PxALP1 gene was cloned and the protein primary structure was deduced. A classic alkPPc （ alkaline phosphatase homologues） domain was found in the 79th - 513th amino acid residue by SMART analysis, and a membrane bound domain was found through SWISS -MODEL homology model construction. Both of them indicated that PxALP1 was a potential membrane bound alkaline phosphatase. Phylogenetic analysis showed that diamondback moth PxALP1 and membrane combine alkaline phosphatase of Lepidoptera insect silkworm had the closest relationship. BLAST aligning exhibited that the identity between PxALP1 and silk- worm BmAlpm was 36.3% and the similarity was 50.3%, which proved that there was high conservation be- tween them.