A comparative transcriptome analysis focusing on immune responses of Asian swamp eel following infection with Aeromonas hydrophila

Abstract Asian swamp eel (Monopterus albus), an economically important fish species in China and other Asian countries, is susceptible to Aeromonas hydrophila infection. A deeper understanding of the Asian swamp eel immune system and its genes related to the response to bacterial infection is necessary for disease control in this species. Herein, we analysed the transcriptomic profile of spleen from Asian swamp eel challenged with A. hydrophila by using the Illumina-based paired-end sequencing method. More than 99.39% clean reads were successfully mapped to the reference genome of M. albus, including 1501 differentially expressed genes (DEGs), of which 928 were upregulated and 573 were downregulated. Additionally, 5911 terms were enriched in Gene Ontology (GO) analysis, and 284 pathways were identified in Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. The reliability of the transcriptome data was validated by quantitative PCR (qPCR). Enrichment analysis of DEGs identified major immune-related pathways, including Toll-like receptor, complement and coagulation cascades, and T- and B-cell receptor signalling pathways. Our results provide valuable information for further analysis of the mechanisms underpinning M. albus defences against A. hydrophila.