茶尺蠖几丁质合成酶基因克隆及其在表皮中的表达.docVIP

 n Chitin synthase (CHS) gene in epidermis of Ectropis obliqua Prout# Liang Yuerong, Lin Chen, Wang Luoren, Ye Jianhui, Lu Jianliang** 5 10 15 20 25 30 35 (Zhejiang University Tea Research Institute, Hangzhou 310058) Abstract: Ectropis obliqua Prout is a major pest in tea fields and chitin synthase (CHS) plays an important role in biosynthesis of chitin and growth of the pest. A cDNA sequence encoding the CHS and its expression pattern during development of E. obliqua were investigated. The CHS cDNA sequence was 5496 bp nucleotides, with an open reading frame of 4692 bp encoding a protein of 1563 amino acids. It belonged to CHS-A member of CHS gene family. The CHS-A expression was the strongest in the third and fourth instar larvae, during which the growth rate of E. obliqua larvae was the rapidest. Catalysis model of CHS-A enzyme in E. obliqua was also hypothesized according to the specific motifs and topological structure prediction of the protein. This study provided an important information for the further research on development of RNA interference (RNAi) technology to control E. obliqua. Key words: Tea science; Ectropis obliqua; tea pest; chitin synthase; gene cloning; biological control 0 Introduction The insect cuticle protects insect from external attack and play an important role in insect wriggling movement. Chitin, a polymer of N-acetyl-β-D-glucosamine, is a major component of insect cuticle. Chitin functions as scaffold material and is always associated with cuticle proteins, which determines the mechanical properties of the cuticle[1,2]. Chitin synthase (CHS) catalyzes the chitin biosynthesis and it is indispensable to insect growth and development. The CHS genes were cloned from many insects[3, 4, 5, 6]. CHS genes were a gene family and they were classified into CHS-A and CHS-B. CHS-A expressed in the epidermis and trachea and CHS-B in the peritrophic matrices[6,7]. In spite of the increasing information on insect chitin synthases, knowledge on