Comparative transcriptome analysis reveals immunoregulation mechanism in the spleen of large yellow croaker (Larimichthys crocea) in response to Vibrio harveyi infection

Large yellow croaker (Larimichthys crocea) is a commercially important fish species worldwide, but high-density cultivation has led to serious diseases especially by Vibrio harveyi. Understanding the molecular response of large yellow croaker to V. harveyi infection is vital for the development of effective measures to combat the disease. In this study, RNA-Seq was performed on the spleen of uninfected and V. harveyi-infected large yellow croaker. A total of 7527 differentially expressed genes (DEGs) were identified, with 4413 up-regulated and 3114 down-regulated genes. Functional enrichment analysis revealed that several immune-related pathways were highlighted, including Toll-like receptors (TLRs) signaling pathway, apoptosis, p53 signaling pathway, and lysosome. In the TLRs signaling pathway, up-regulated genes included IL1b, bactericidal permeability-increasing protein, and IL12b, while down-expressed genes included tlr3 and irf3. The apoptosis pathway showed up-regulated genes such as casp6, bcl-2-like protein, and cytochrome c, and down-expressed genes such as granzyme B, sptan1, and FADD-Fas (tnfrsf6)-associated via death domain. These results suggest that V. harveyi infection induced inflammatory response and apoptotic cell death in the spleen of large yellow croaker. This study provides valuable insights into the molecular mechanisms underlying the immune response of large yellow croaker to V. harveyi infection