Abstract

Aquaculture is critical to global food security, yet bacterial epidemics threaten its sustainability. The defense mechanisms of fish remain poorly understood, hindering effective disease management. This study investigates the temporal immune response of the economically important marine teleost Larimichthys polyactis to Pseudomonas plecoglossicida , a pathogen that causes lethal white-nodule disease of internal organs. Integrated analyses of histopathology, biochemistry, and TUNEL assays revealed that infection triggered hepatic granulomatous nodulation and oxidative stress, culminating in apoptosis at 72–96 h post-infection (hpi). Transcriptomic and proteomic profiling showed the distinct time-dependent and stage-specific enrichment patterns of DEGs and DEPs. The early stages (6–48 hpi) involved endocrine regulation, immune signal transduction, and energy metabolism, whereas the later stages (72–96 hpi) were characterized by programmed cell death and immune defense. Integrated multi-omics analysis and expression validation indicated that upregulation of the apoptotic pathway may be associated with the host response to P. plecoglossicida infection. These findings deepen our insights into the dynamic response mechanisms of marine teleosts against P. plecoglossicida infection and provide a theoretical framework for host-pathogen interactions.