Transcriptomic analysis of the immune response against A. hydrophila infection in striped catfish Pangasianodon hypophthalmus

Abstract

As an emergent bacterial pathogen in aquaculture, A. hydrophila has caused considerable losses to the striped catfish aquaculture industry. Efficient transcriptome research has been widely used to study the immune response of fish against pathogens. This study firstly reported the effect of A. hydrophila infection at 0, 4, 12, 24, 36, and 48 h on Pangasianodon hypophthalmus at the transcriptome level. The changes in multiple immune indices indicated that the earlier stages, including 4, 12, and 24 h, were key time points during A. hydrophila infection. Accordingly, 6824, 2674, and 1571 differentially expressed genes (DEGs) were identified between each key infection time (4, 12, and 24 h) versus 0 h. Most of the DEGs were enriched in the functional categories of positive regulation of response to stimulus, positive regulation of immune system process, activation of immune response, positive regulation of immune response, and defense response. Further analysis based on the short time-series expression miner methods indicated that the genes significantly fluctuated in response to A. hydrophila infection and were enriched in cytokine-related pathways, including cytokine-cytokine interaction, the interleukin 17 signaling pathway, Th cell differentiation, and the chemokine signaling pathway. Weighted co-expression network analysis was applied to identify 14 hub genes involved in the immune response against A. hydrophila infection, and a corresponding gene regulatory network was constructed. The findings in this study provide further in-depth insights into the immune response of P. hypophthalmus against A. hydrophila infection, which could be implicated in the future prevention and treatment of infectious diseases in aquaculture.