Abstract:Scavenger receptors (SRs) are a family of structurally diverse and functionally versatile transmembrane glycoproteins molecules that play critical roles in immune defense, inflammatory regulation, and tissue homeostasis. Currently, no studies have systematic identified the scavenger receptor gene family in turbot (Scophthalmus maximus) and explored its role in the immune response. To systematically identify the scavenger receptor gene family in turbot and explore their functions during Vibrio anguillarum infection. This study conducted a genome-wide identification of scavenger receptor family members in turbot based on its genomic database using bioinformatics approaches. Annotation and confirmation of these genes were performed through domain analysis and phylogenetic analysis.The tissue distribution of scavenger receptor genes was analyzed in eight healthy turbot tissues (blood, skin, gill, liver, spleen, intestine, head kidney, and brain) using Quantitative Real-time polymerase chain reaction (qPCR). Additionally, their expression patterns in mucosal tissues (gill, skin, and intestine) were examined during the early stages of V. anguillarum infection. The results show a total of 16 scavenger receptor genes were identified in turbot. With the exception of mrc1a, which was undetectable in the liver, and ldlr, which was not expressed in blood, the selected scavenger receptors were widely expressed across all eight tissues in healthy turbot. In the early stage of V. anguillarum infection, scara4 and scarf1 in the three mucosal tissues of turbot showed an upward trend at each detection time point. The remaining 10 scavenger receptors exhibited differentiated expression characteristics in different tissues and at different time points after infection. For instance, scara2/marco and scarf2 were significantly upregulated in skin tissues at each time point after infection, while scarb1 was significantly downregulated in intestinal tissues at each time point after infection. These findings suggest that scavenger receptor genes in turbot mucosal tissues play distinct functional roles in response to V. anguillarum infection across different tissues. The results of this study provide a reference for analyzing the molecular genetic mechanism of disease-resistant traits.