Cypermethrin exposure induces metabolic and stress-related gene expression in copepodid salmon lice (Lepeophtheirus salmonis).
Cypermethrin has been administered for decades to control salmon lice (Lepeophtheirus salmonis) infestations in Atlantic salmon farming regions globally. However, resistance to cypermethrin and other available therapeutants has threatened the sustainability of this growing industry. To better understand the effects of cypermethrin on L. salmonis, a 38K oligonucleotide microarray and RT-qPCR analyses were applied to pools of copepodid larvae exposed to 1.0ppb cypermethrin or seawater controls for 24h. Phenotypic assessments and global gene expression profiles showed a significant disruption of homeostasis in copepodid L. salmonis exposed to cypermethrin. Multiple degradative enzymes were overexpressed in cypermethrin-treated lice including five trypsin-like serine proteases and three cytochrome p450s CYP3a24 (p=0.03, fold change (FC)=3.8; GenBank accession no. JP326960.1), CYP6w1 (p=0.008, FC=5.3; GenBank accession no. JP317875.1), and CYP6d4 (p=0.01; FC=7.9; GenBank accession no. JP334550.1). These enzymes represent preliminary markers for understanding the physiological response of L. salmonis to cypermethrin exposure. A general stress response was also observed in cypermethrin-treated lice which included differential expression of cell signaling genes involved in the induction of cell growth, solute transport, and metabolism. Lastly, a consensus-based analysis was completed with two previously published L. salmonis transcriptome studies revealing genes that respond to cypermethrin, emamectin benzoate (another delousing agent) and hyposalinity. This included concordant differential expression of heat shock beta-1, ammonium transporter Rh types B, and 72kDa type IV collagenase across different L. salmonis studies. This is currently the most comprehensive transcriptome assessment of chemical exposure on the first infectious stage of L. salmonis, providing novel markers for studying drug resistance and general stress in this important parasite.
Hoplite Lab, Department of Pathology & Microbiology, Atlantic Veterinary College, University of Prince Edward Island, 550 University Ave, Charlottetown, PE, C1A 4P3, Canada. Electronic address: jpoley@upei.ca.
Jordan D
JD
Poley
Hoplite Lab, Department of Pathology & Microbiology, Atlantic Veterinary College, University of Prince Edward Island, 550 University Ave, Charlottetown, PE, C1A 4P3, Canada. Electronic address: lbraden@upei.ca.
Laura M
LM
Braden
Centre for Biomedical Research, Department of Biology, University of Victoria, Victoria, BC, V8W 3N5, Canada. Electronic address: amessmer@uvic.ca.
Amber M
AM
Messmer
Hoplite Lab, Department of Pathology & Microbiology, Atlantic Veterinary College, University of Prince Edward Island, 550 University Ave, Charlottetown, PE, C1A 4P3, Canada. Electronic address: swhyte@upei.ca.
Shona K
SK
Whyte
Centre for Biomedical Research, Department of Biology, University of Victoria, Victoria, BC, V8W 3N5, Canada. Electronic address: bkoop@uvic.ca.
Ben F
BF
Koop
Hoplite Lab, Department of Pathology & Microbiology, Atlantic Veterinary College, University of Prince Edward Island, 550 University Ave, Charlottetown, PE, C1A 4P3, Canada. Electronic address: mfast@upei.ca.
Mark D
MD
Fast
D000818:Animals; D019295:Computational Biology; D033342:Copepoda / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D029941:Fish Proteins / Q000235:genetics*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects*; D016678:Genome / Q000235:genetics; D007306:Insecticides / Q000494:pharmacology*; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D011722:Pyrethrins / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013312:Stress, Physiological / Q000235:genetics*; D059467:Transcriptome / Q000187:drug effects / Q000235:genetics*
D029941:Fish Proteins; D007306:Insecticides; D011722:Pyrethrins; D012333:RNA, Messenger; C017160:cypermethrin
Cypermethrin; Lepeophtheirus salmonis; cytochrome p450; pesticide resistance; protease; salmon lice