The Pathology and Splenic Transcriptome Profiling of <i>Trionyx sinensis</i> Challenged with <i>Bacillus cereus</i>

Abstract

The pathogenic Bacillus cereus strain XS0724 isolated from China can cause high lethality to Trionyx sinensis, but little information is available on their detailed interactions. In this study, histopathologic profiling indicated that B. cereus caused vacuolization and cell necrosis in the liver, spleen, kidney, and intestine. The identification of the virulence factor genes non-hemolytic enterotoxin (Nhe), hemolysin BL (Hbl), and enterotoxin FM (entFM) confirmed bacterial pathogenicity. Splenic transcriptomic sequencing at 96 h post-infection identified various immune-related genes mapped to diverse gene families, including interleukin, complement, chemokine, and interferon. The differentially expressed genes (DEGs) were enriched in 2174 GO terms: 1694 in biological processes, 138 in cellular components, and 342 in molecular functions. Further KEGG enrichment indicated that DEGs were primarily associated with the phagosome, NF-kappa B signaling pathway, and PI3K-Akt signaling pathway. The DEGs and enriched pathways may be involved in the elimination of invasive B. cereus. These data laid the foundation for elucidating the potential molecular mechanisms in this bacterial infection process, and provided robust genetic evidence for subsequent work on resistance genes of T. sinensis.

Keywords

• resident bacteria
• opportunistic infection
• toxins
• immune response
• aquaculture