Work

Transcriptomic defense mechanism of Japanese Eel (Anguilla japonica) against Edwardsiella anguillarum infection after bath immunization with Bacillus subtilis spores displaying OmpA of E. anguillarum

Year: 2025

Type: article

Abstract: This study explored the effectiveness and underlying transcriptomic mechanisms of bath immunization using Bacillus subtilis spore-displayed outer membrane protein A (OmpA) against the infection of Edwardsiella anguillarum, a pathogen causing hemorrhagic septicemia in Japanese eels (Anguilla japonica). Eels were immunized with B. subtilis spores presenting OmpA (WA group) or inactivated whole-cell E. anguillarum (EA group), while controls were exposed to B. subtilis spores (WC group) or PBS (Con group). After 28 days (d), all groups were challenged with E. anguillarum, and mortality was monitored for 14 d. Histopathology and gene expression were assessed 48 hours (h) post-infection. The WA and EA groups showed significantly lower mortality rates (64.3% and 57.1% relative survival, respectively) compared to the Con group. Histopathological examination revealed varying degrees of liver and kidney damage in infected groups, with the most severe effects observed in two control groups. Transcriptomic analysis identified 1973 differentially expressed genes (DEGs) in the WA infected group (WA_inf) and 866 in the EA infected group (EA_inf) relative to the Con infected group (Con_inf). Gene Ontology (GO) and KEGG annotation of DEGs highlighted 5 GO terms associated with "catalytic activity", "binding", "cell part", "membrane part", "biological regulation", and "cellular process", and 4 KEGG pathways related to "Cancer", "Infectious disease", "Immune system", and "Signal transduction". Enrichment analysis emphasized 3 GO terms—transporter activity, heme binding, and oxidoreductase activity—and 10 immune-related KEGG pathways, particularly those involving phagosomes, in the WA_inf vs WC_inf (WC infected group) comparison. A chord diagram analysis identified 17 key DEGs involved in immune regulation against E. anguillarum post-bath immunization. A protein-protein interaction network further pinpointed three DEG-encoded proteins crucial for the immune response to E. anguillarum following immunization. The study underscores the potential of bath immunization to boost eel survival against E. anguillarum infection and elucidates the molecular mechanisms mediating the immune response.

Source: Aquaculture Reports

DOI: 10.1016/j.aqrep.2025.102856

Authors: Minxia Chen, Zihao Chen, Guanghua Sun, Qiuhua Yang, Songlin Guo

Institutions: Jimei University, Fujian Fisheries Research Institute

Language: English

Topic: Aquaculture disease management and microbiota

Subfield: Immunology

Field: Immunology and Microbiology

Domain: Life Sciences

SDG: Good health and well-being

Open Access status: gold

Estimated APC paid: $2,640