Gene expression of esterases in Dendroctonus valens LeConte (Curculionidae: Scolytinae) exposed to α-pinene

Several bark beetles transform toxic monoterpens secreted by their host into aggregation pheromones. Although Dendroctonus valens is attracted by R-(+)-α-pinene and S-(-)-α-pinene and transform it, no aggregation pheromone has been identified for this species. Histological and ultrastructural studies indicate that this biotransformation take place in epithelial cells of alimentary canal, suggesting that processing of this monoterpens could be associated to detoxification processes. One of the most common enzymes involved in detoxification of xenobiotics is carboxylesterases. Previous histoquemistry estudies have shown an increase of non-specific esterase activity in alimentary canal when D. valens is expose to α-pinene. The aim of this study is to identify different esterase gene in D. valens, observe presence of esterase gene expression in alimentary canal and antennae of D. valens exposed to α-pinene by RT-PCR, as well as complete amplification of esterase gene by RACE. Using degenerated primers, we obtained a sequence of 300 bp that is 60% similar to Tribolium castanum carboxylesterase. With this sequence we design specific primers to amplify a sequence of 1400pb in alimentary canal and antennae by RT-PCR. Also, by concatenating the overlapping sequences obtained by 3’ and 5’ RACE a putative full-length cDNA of 1951pb was generated.