Immunogene expression analysis in betanodavirus infected-Senegalese sole using an OpenArray® platform

Area of Science:

• Aquatic animal health
• Fish immunology
• Molecular virology

Background:

• Betanodaviruses cause significant disease outbreaks in aquaculture.
• Understanding host-pathogen interactions is crucial for disease management in Senegalese sole.

Purpose of the Study:

• To compare the transcriptomic response of Senegalese sole to two betanodaviruses with differing virulence.
• To elucidate the molecular mechanisms underlying differential disease outcomes.

Main Methods:

• Quantitative PCR (OpenArray® platform, TaqMan™) was used to assess the transcription of 112 genes.
• Gene expression was analyzed in head kidney and pooled eye/brain samples at two time points post-infection.
• Two betanodavirus isolates, one highly virulent (wSs160.3) and one moderately virulent mutant, were used.

Main Results:

• The highly virulent isolate induced significantly higher gene expression in both organs compared to the moderately virulent strain.
• Gene expression changes were more pronounced at 2 days post-infection with the wild-type isolate than at 3 days.
• The virulent virus triggered an exacerbated interferon 1 response, contributing to apoptosis and immunopathology, while the mutant showed altered viral recognition pathways.

Conclusions:

• Virulence in betanodaviruses is associated with a stronger host transcriptomic response and an immunopathological interferon 1 response.
• Host recognition pathways, including myd88 and tbkbp1, play a role in the differential response to betanodavirus infection.
• Genes such as rtp3, sacs, and isg15 may be key players in the host response to highly virulent betanodavirus infection.