Transcriptomic analysis provides molecular insights into the innate immune defense of Mactra veneriformis against...

Mactra veneriformis is an economically important bivalve mollusc in China, but its aquaculture is frequently threatened by Vibrio infections, particularly Vibrio alginolyticus. To investigate the molecular immune response of M. veneriformis to V. alginolyticus, we performed RNA-seq analysis of hepatopancreatic tissues collected at 48 h post-infection, the peak mortality time point, with PBS-injected individuals used as controls. Infection with V. alginolyticus caused severe histopathological damage in the hepatopancreas and resulted in a cumulative mortality of 53.3% over 14 d, compared with 3.3% in the control group. Transcriptomic analysis identified 2623 differentially expressed genes (DEGs), including 1585 significantly up-regulated genes and 1038 down-regulated genes. KEGG enrichment analysis demonstrated that DEGs were significantly enriched in immune related and metabolism pathways, including the JAK-STAT signaling pathway, RIG-I-like receptor (RLR) signaling pathway, and cytochrome P450 (CYP450) signaling pathway. Collectively, these findings revealed candidate immune related genes (tlr3, tlr5, myd88, nfkb1, il-17d, and ifi44l), a putative TLR-MyD88-NF-κB signaling axis, and KEGG signaling pathways, including JAK-STAT, RLR and CYP450, that may be involved in the innate immune response of M. veneriformis to V. alginolyticus infection. These results provide a transcriptomic basis for understanding host-pathogen interactions in this species and highlight candidate genes and pathways for future functional validation and potential application in disease-resistance breeding.