Application of Cydia pomonella expressed sequence tags： Identification and expression of three general odorant binding proteins in codling moth

The codling moth, Cydia pomonella, is one of the most important pests of pome fruits in the world, yet the molecular genetics and the physiology of this insect remain poorly understood. A combined assembly of 8？341 expressed sequence tags was generated from Roche 454 GS-FLX sequencing of eight tissue-specific cDNA libraries. Putative chemosensory proteins （12） and odorant binding proteins （OBPs） （18） were annotated, which included three putative general OBP （GOBP）, one more than typically reported for other Lepidoptera. To further characterize CpomGOBPs, we cloned cDNA copies of their transcripts and determined their expression patterns in various tissues. Cloning and sequencing of the 698？nt transcript for CpomGOBP1 resulted in the prediction of a 163 amino acid coding region, and subsequent RT-PCR indicated that the transcripts were mainly expressed in antennae and mouthparts. The 1？289 nt （160 amino acid） CpomGOBP2 and the novel 702 nt （169 amino acid） CpomGOBP3 transcripts are mainly expressed in antennae, mouthparts, and female abdomen tips. These results indicate that next generation sequencing is useful for the identification of novel transcripts of interest, and that codling moth expresses a transcript encoding for a new member of the GOBP subfamily.

Identification and initial characterization of the 3＇ end of gene transcripts encoding putative members of the pheromone receptor subfamily in Lepidoptera

Semiochemicals, including pheromones and kairomones, used in pest man- agement programs reduce the need for chemical insecticides, and understanding their interactions with their membrane receptors may help make them more effective in the field. Identification of odorant receptors in the Lepidoptera has mainly been achieved us- ing bioinformatics to search DNA sequences generated by genome or expressed sequence tag （EST） sequencing projects. This study reports a rapid method to identify members of the pheromone receptor subfamily in Lepidoptera. Degenerate oligonucleotide primers were designed against a conserved amino acid sequence in the carboxyl terminus of known lepidopteran pheromone receptors, and the primers were used in a 3＇ rapid amplifica- tion of complementary DNA （cDNA） ends procedure. Polymerase chain reaction products generated from seven different lepidopteran species were TA cloned and sequenced. The cDNA sequences of 25 transcripts were determined to encode potential members of the pheromone receptor subfamily. These cDNAs ranged from 238 to 642 bp and encoded 49-54 amino acids of the carboxyl terminus. Analysis of the 3＇ untranslated region reveals that most of the transcripts contain multiple polyadenylation signal sequences, and in the case ofManduca sexta, an alternate polyadenylation signal appears to be used in transcript processing. The 3＇ untranslated region was also useful in determining unique receptors en- coded by transcripts having highly similar nucleotide and amino acid sequences. Overall, this technique provides a complementary method of pheromone receptor identification in EST sequencing projects, or can be used as a stand-alone method in conjunction with 5＇ rapid amplification of cDNA ends procedures.