Identification and characterization of the septin gene family in rainbow trout (Oncorhynchus mykiss) and their expression profiles in response to Vibrio anguillarum and Aeromonas salmonicida infections

Abstract

Septins are cytoskeletal GTP-binding proteins that play critical roles in host defense against bacterial infections. Rainbow trout (Oncorhynchus mykiss), a commercially valuable and widely farmed salmonid species, has not been systematically investigated with regard to its septin gene family. In this study, we identified 34 septin genes in rainbow trout and categorized them into four subgroups based on phylogenetic relationships. Syntenic, structural, and motif analyses revealed their conserved features, with strong domain and sequence homology observed across species. Tissue- and gene-specific expression patterns were evaluated in healthy individuals. Moreover, expression profiling following bacterial challenge with Vibrio anguillarum and Aeromonas salmonicida revealed significant transcriptional changes in septin genes, suggesting their involvement in the regulation of innate immune responses. This study provides the first comprehensive characterization of the septin gene family in rainbow trout and highlights their complex and essential roles in host immunity, offering valuable insights into their immunoregulatory functions in teleosts.