Abstract
BACKGROUND: Aeromonas hydrophila, a widespread aquatic pathogen, can infect a range of aquatic organisms, such as fish and crustaceans (including Eriocheir sinensis). Understanding the host resistance mechanism against A. hydrophila infection is of significant importance. RESULTS: In this study, the metabolic and transcriptomic profiles of crabs (E. sinensis) at different stages of A. hydrophila infection (early-infection stage: Ah_6h, mid-infection stage: Ah_24h, and late-infection stage: Ah_72h) were investigated. Metabolomic analysis showed that differentially expressed metabolites were predominantly enriched in purine metabolism pathways. Transcriptomic analysis revealed that the infection might activate the crab's immune response through key signaling pathways, including NF-κB and RIG-I-like receptor pathways, at the early-infection stage, while potentially maintaining immune function throughout infection via apoptosis, phagocytosis, and lysosomal pathways. Notably, the mid-infection stage was the pivotal period in the regulation of the crab's immune response, with the highest levels of differential metabolites and genes. Integrated transcriptomic and metabolomic analysis further highlighted the potential key roles of the tricarboxylic acid (TCA) cycle and purine and pyrimidine metabolisms in the immune response of E. sinensis against A. hydrophila. CONCLUSIONS: These findings provide a better understanding of the immunity of E. sinensis in response to bacterial infection.