In silico transcriptome analysis of cuticle-related genes associated with delousing drug responses in the sea louse Caligus rogercresseyi

The present report examined changes in cuticle protein expression in sea lice strains resistant or susceptible to delousing drugs. Specifically, the transcriptome profiles of genes related to cuticle biosynthesis were evaluated in the sea louse Caligus rogercresseyi in response to the antiparasitics azamethiphos (Bayer (R)) and deltamethrin (AlphaMax (R)). For bioassays, putative cuticle-related genes from sea lice exposed to deltamethrin or azamethiphos were evaluated using high-throughput transcriptome sequencing and RT-qPCR analysis. From the previously reported C. rogercresseyi transcriptome, a total of 479 transcripts were annotated as proteins linked to cuticle formation. RNA-Seq analysis evidenced high transcription levels of cuticle precursors during the larval stage, while in adults cuticle proteins were highly regulated. Furthermore, 234 transcripts were highly regulated in response to delousing drugs, such as cuticle proteins, P4H, PDI, and chitinase. Principle components analysis revealed a high correlation between exposure to azamethiphos and cuticle precursors, suggesting a putative modulation of organophosphates against cuticle-related proteins in sea lice. Moreover, transcript expression of collagen and cuticle genes revealed significant differences between sexes. These results suggest a modulation by C. rogercresseyi of cuticle biogenesis in response to delousing drugs. Statement of relevance The present report examined changes in cuticle protein expression in sea lice exposed to delousing drugs. The study gathers high-throughput sequencing features to suggest novel aspects of the drug response to organophosphates and pyrethroids used by the salmon aquaculture industry. (C) 2015 Elsevier B.V. All rights reserved.