Screening and preliminary analysis of antimicrobial peptide genes in Octopussinensis

Antimicrobial peptides (AMPs) are small molecular peptides that widely exist in organisms to resist external microbial invasion and play a crucial role in the host's immune defense system. Owing to their functions of efficient broad-spectrum killing of pathogenic microorganisms, immune enhancement, and intestinal health improvement, they have emerged as a focal point in research on the immune defense of aquatic animals in recent years. In this study, a total of 105 putative AMP-derived genes from the genome were screened, and seven candidate AMPs were finally identified by analyzing the differential expression results of the hepatopancreas and the white body transcriptomes combined with machine learning algorithms. Furthermore, the seven synthesized antimicrobial peptides were demonstrated to have good antimicrobial activity. Among them, GAP1 and Big Defensin showed the strongest antibacterial activity. GAP1 and Big Defensin exhibited antibacterial activity against four bacteria (Escherichia coli, Vibro parahaemolyticus, Staphylococcus aureus, and Bacillus subtilis) at low concentrations of 5-10 μM and 3.2-12.9 μM respectively. These data will contribute to the development of AMP-based aquatic drugs.