Abstract: 【Aim】This study aims to integrate the evolutionary characteristics of antimicrobial peptides (AMPs) in mosquitoes and their expression patterns in the salivary glands to reveal the adaptive changes throughout their evolutionary process. 【Methods】 We retrieved the genomes and genes of four kinds of AMPs, including gambicin, attacin, cecropin and defensin, from 10 mosquito species (four species from Culicinae and six species from Anophelinae) in VectorBase to improve the gene bank of AMPs in mosquitoes. Subsequently, we constructed phylogenetic tree of AMPs using the maximum likelihood method. Gene duplication and gene deletion were examined using Notung v2.9.1.5 based on the phylogenetic trees of AMPs. Collinearity of AMP genes was assessed using MCScanx. The selection pressure on each AMP gene was analyzed using HyPhy v.2.5.62. We utilized publicly available transcriptomic data of the salivary glands to systematically analyze the expression patterns of these AMP genes in the salivary glands. 【Results】There were noticeable differences in the types and numbers of AMP genes across mosquito species. Phylogenetic analysis showed that AMP genes clustered by their taxonomic origin (Culicinae and Anophelinae), suggesting conserved amino acid sequences, as corroborated by the selection pressure test. AMP genes in mosquitoes exhibited multiple gene duplications and gene deletions potentially corresponding to shifts in host feeding behaviors. Collinearity analysis result indicated that most AMP genes are located within collinear blocks, suggesting the conservation of AMP genes in mosquitoes. Integrating the expression patterns of AMP genes in the salivary glands with gene evolution and selection pressure, we hypothesized that a branch of cecropin may have undergone functional gain. 【Conclusion】Our study highlights the adaptability of AMP genes in mosquitoes, suggesting their close relationship with host selection and pathogen infection. The evolutionary traits and expression patterns of AMPs in mosquitoes enhance their survival strategies and underscore their role as key factors in disease vectoring ability. These findings provide new insights into the molecular adaptations of mosquito immune systems and their implications for pathogen transmission.

Key words: Mosquitoes, salivary glands, antimicrobial peptides, gene duplication, gene deletion, adaptive evolution