Gene expression response to a nematode parasite in novel and native eel hosts

Area of Science:

• Ecology
• Parasitology
• Genomics

Background:

• Invasive parasites threaten host populations globally.
• Novel hosts often lack immunity to invasive parasites due to a lack of co-evolution.
• Susceptibility in new hosts is often linked to immune deficits.

Purpose of the Study:

• To investigate gene expression changes in Japanese eels (native hosts) and European eels (novel hosts) infected with Anguillicola crassus.
• To compare the immune and physiological responses of native and novel hosts to parasitic infection.
• To understand the molecular mechanisms underlying host susceptibility to invasive parasites.

Main Methods:

• Experimental infection of Japanese and European eels with Anguillicola crassus.
• RNA sequencing (RNA-seq) of head kidney tissue at 3 and 23 days post-infection.
• Differential gene expression analysis to identify host responses.

Main Results:

• The novel host (European eel) showed broader and more diverse gene expression changes than the native host (Japanese eel).
• The novel host regulated immune genes at both early time points, while the native host showed minimal immune gene regulation.
• Reduced expression of cell respiration genes in the novel host suggests impaired energy metabolism.

Conclusions:

• Host susceptibility to novel parasites involves disruption of physiological processes beyond just the immune response.
• Gene expression patterns in eels mirror those seen in other vertebrate groups, indicating a conserved response to novel parasitic infections.
• Understanding these molecular disruptions is key to managing invasive parasite impacts.