A transient receptor potential is expressed with multiple splicing isoforms in the Codling Moth Cydia pomonella

Transient receptor potential (TRP) channels are an ancient family of cation channels that have been found in many eukaryotic organisms, from yeast to human. Since the first identification of a TRP in Drosophila melanogaster , several TRPs have been identified and functionally characterized in other insect species. TRPs are involved in the reception of physical and chemical stimuli but also of metabotropic triggers, mediating membrane depolarization in response to environmental stimuli. Regulation of TRPs at multiple levels, including transcription, mRNA splicing, protein synthesis/processing in ER and Golgi apparatus as well as membrane trafficking, and post-translational modifications have been reported. It is speculated that different TRP splice forms serve various distinct functional roles. Identification of TRP candidates in insect pests and understanding their functional role in sensing environmental cues of different modalities is intriguing and may open for novel applications in agriculture. For instance, TRP-active compounds reported to have somatosensory properties were found to be active on insect pests at the electrophysiological and behavioral level. Using next generation sequencing of the antennal transcriptome, we have identified five candidate TRPs in the fruit pest Cydia pomonella (L.). A phylogenetic analysis revealed that candidate antennal TRPs belong to the TRPA, TRPC and TRPV sub-families, known to be involved in various sensory modalities such as noxious heat avoidance, hygrosensation and phototransduction in D. melanogaster . The full-length sequence encoding one of these five TRPs was obtained by RACE-PCR, and its expression pattern was investigated in different body parts of adult moths, in both males and females. The existence of multiple splicing isoforms of this candidate TRP was demonstrated by PCR, using primers crossing regions of alternative splicing. Interestingly, while some isoforms were expressed in all body parts, others were differentially expressed, depending on sex and body parts