Abstract:Aeromonas hydrophila is one of the main pathogens seriously endangering mandarin fish farming and production. In order to explore the changes in host gene expression levels in A. hydrophila infection, screen for immune-related genes, and analyze the molecular mechanism of Siniperca chuatsi infected with Aeromonas hydrophila in response to pathogenic bacterial infection. The head kidney tissues of the infected and control groups were collected 24 h after inoculation and used for mRNA extraction, and transcriptome sequencing was performed using high-throughput sequencing technology. A total of 53 040 single genes (unigenes) were obtained from the original sequencing data through de novo assembly. The results of gene differential expression analysis showed that there were 526 differentially expressed genes, of which 254 were upregulated and 272 were down-regulated in the infected and control groups. Among the differentially expressed genes, several key genes involved in the immune response, such as interleukin-8, interleukin-6 receptor, interleukin 17 receptor, lysozyme, complement receptor type 1, antigen processing and presentation, serine protease inhibitor, and E3 ubiquitin-protein ligase were present. Gene ontology analysis revealed that the different genes were mainly involved in immune response and inflammation. A KEGG analysis showed that there were 89 significantly enriched and immune-related metabolic pathways mainly involved with endocytosis and phagosomes. Real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) verification was performed on seven DEGs, and the results showed that RT-qPCR was consistent with RNA-Seq analysis. These results lay a theoretical foundation for a follow-up study of gene function and in-depth exploration of the molecular defense mechanism of S. chuatsi against pathogenic microorganism infection.
