Gene Cloning And Preliminary Function Study Of Odorant Binding Protein In Agasicles Hygrophila (Coleoptera: Chrysomelidae)

Insect has evolved into a very specific and sensitive olfactory system for a long time. This system plays a critical key in behavioral reactions of insects, such as food seeking, mating, oviposition and evading predators. Various different proteins participate in the olfactory process, while the odorant binding proteins are the first step in the olfaction biochemical reactions, which can identify and screen volatile odors form host plants and other insects. Agasicles hygrophila is a monophagous insect, mainly feeding on Alternanthera philoxeroides. In order to study odorant binding proteins' role in the process of Agasicles hygrophila idientifing host plants, to preliminary clarify the significance of odorant binding proteins in the olfactory process, several results showed as follow.1) We screened 28 odorant binding protein genes in the Agasicles hygrophila transcriptome by Blastx, including Classic OBPs?Minus-C OBPs and Atypical OBPs,8,18 and 2 respectively, and most odorant binding proteins belong to the Minus-C OBPs.2) Three odorant binding protein genes were cloned, their open reading frame is 351 bp,423 bp and 408 bp respectively, which can encloding 116,140 and 135 amino acids. OBPs have the typical characteristics, belonging to the low molecular weight, acidic and hydrophilic protein.3) Real-time PCR technology was used to study on the expression of the three OBP genes in different tissues of Agasicles hygrophila. The results showed that the expression of the three kinds of odorant binding proteins was highest in the antennae of male and female insects. The expression level of OBP 12 and OBP 14 in female antennae was higher than male antennae, whereas the expression level of OBP24 in female was higher than male antenna. In addition to the expression in the antennae, OBP 14 also expressed in heads and legs and OBP24 expressed in the heads, legs and wings, too.4) The prokaryotic expression vectors were constructed, and the expression of OBP 12 and OBP 14 was successfully induced, which laid a good foundation for the structural characteristics and physiological functions of the protein for the further study.