title: Major host transitions are modulated through transcriptome-wide reprogramming events in Schistocephalus solidus, a threespine stickleback parasite.
abstract: Parasites with complex life cycles have developed numerous phenotypic strategies, closely associated with developmental events, to enable the exploitation of different ecological niches and facilitate transmission between hosts. How these environmental shifts are regulated from a metabolic and physiological standpoint, however, still remain to be fully elucidated. We examined the transcriptomic response of Schistocephalus solidus, a trophically transmitted parasite with a complex life cycle, over the course of its development in an intermediate host, the threespine stickleback, and the final avian host. Results from our differential gene expression analysis show major reprogramming events among developmental stages. The final host stage is characterized by a strong activation of reproductive pathways and redox homoeostasis. The attainment of infectivity in the fish intermediate host-which precedes sexual maturation in the final host and is associated with host behaviour changes-is marked by transcription of genes involved in neural pathways and sensory perception. Our results suggest that un-annotated and S. solidus-specific genes could play a determinant role in host-parasite molecular interactions required to complete the parasite's life cycle. Our results permit future comparative analyses to help disentangle species-specific patterns of infection from conserved mechanisms, ultimately leading to a better understanding of the molecular control and evolution of complex life cycles.
authors.affiliation: Département de Biologie, Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, 1030 avenue de la Médecine, Québec, QC, G1V 0A6, Canada.
authors.forename: François Olivier
authors.initials: FO
authors.lastname: Hébert
authors.affiliation: Department of Neuroscience, Psychology and Behaviour, University of Leicester, Adrian Building, University Road, Leicester, LE1 7RH, UK.
authors.forename: Stephan
authors.initials: S
authors.lastname: Grambauer
authors.affiliation: Department of Neuroscience, Psychology and Behaviour, University of Leicester, Adrian Building, University Road, Leicester, LE1 7RH, UK.
authors.forename: Iain
authors.initials: I
authors.lastname: Barber
authors.affiliation: Département de Biologie, Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, 1030 avenue de la Médecine, Québec, QC, G1V 0A6, Canada.
authors.forename: Christian R
authors.initials: CR
authors.lastname: Landry
authors.affiliation: Département de Biologie, Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, 1030 avenue de la Médecine, Québec, QC, G1V 0A6, Canada.
authors.forename: Nadia
authors.initials: N
authors.lastname: Aubin-Horth
mesh_terms: D000818:Animals; D002589:Cestoda / Q000235:genetics*; D002590:Cestode Infections / Q000469:parasitology*; D005393:Fish Diseases / Q000469:parasitology; D006790:Host-Parasite Interactions; D023701:Smegmamorpha / Q000469:parasitology*; D059467:Transcriptome
keywords: 
  Schistocephalus solidus
  ; bird; cestode; parasite; threespine stickleback; transcriptomics