RNA interference mediated knockdown of the KDEL receptor and COPB2 inhibits digestion and reproduction in the parasitic copepod Lepeophtheirus salmonis

Abstract

Retrograde transport of proteins from the endoplasmic reticulum to the Golgi is an essential part of the secretory pathway that all newly synthesised secreted and membrane proteins in eukaryotic cells undergo. The aim of this study was to characterise two components of the retrograde transport pathway in the parasitic copepod Lepeophtheirus salmonis (salmon louse) on a molecular and functional level. LsKDELR and LsCOPB2 were confirmed to be the salmon louse homologues of the chosen target proteins by sequence similarity. Ontogenetic analysis by qRT-PCR revealed the highest expression levels of both genes in adult females and the earliest larval stage. LsKDELR and LsCOPB2 localisation in adult females was detected by immunofluorescence and in situ hybridisation, respectively. Both LsKDELR and LsCOPB2 were found in the ovaries, the oocytes and the gut.LsKDELR and LsCOPB2 were knocked down by RNA interference in preadult females, which was confirmed by qRT-PCR. LsCOPB2 knock down lice had a significantly higher mortality and failed to develop normally, while both LsCOPB2 and LsKDELR knock down caused disturbed digestion and the absence of egg strings. This shows the potential of LsKDELR and LsCOPB2 as suitable target candidates for new pest control methods.

Exocrine glands of Lepeophtheirus salmonis (Copepoda: Caligidae): Distribution, developmental appearance, and site of secretion

“…This showed that the LsAst1 primers amplified a second gene, EMLSAG00000011131. The in situ hybridization was performed with sections from adult female lice according to Dalvin et al (), with some modifications as described in Tröße et al (). Additionally, the proteinase K treatment was prolonged to 18 minutes.…”

Genomic Characterization and Phylogenetic Position of Two New Species in Rhabdoviridae Infecting the Parasitic Copepod, Salmon Louse (Lepeophtheirus salmonis)

“…In situ hybridization was performed according to Dalvin et al [36] , with some modifications as described in Tröße et al [37] . The digoxigenin labelled (DIG-labelled) sense and antisense RNA probes were made with primers listed in Table 2 .…”

Molecular characterisation and functional analysis of LsChi2, a chitinase found in the salmon louse (Lepeophtheirus salmonis salmonis, Krøyer 1838)

“…In insects, knock down of chitinase has been shown to be essential for hatching, molting and adult eclosion (Zhang et al, 2012;Zhu et al, 2008). The use of RNAi in salmon louse has been reported several times (Campbell et al, 2009;Dalvin et al, 2009;Eichner et al, 2014;Trösse et al, 2014). RNAi of a chitinase in crustaceans has to our knowledge only been reported once in salmon louse (Eichner et al, 2014).…”