Diversity of the Antimicrobial Peptide Genes in Collembola

SIMPLE SUMMARY: Collembola (springtails) are tiny non-insect hexapods living in soil and have an important ecological role as detritivores. How they can survive in the microbe-rich environment for millions of years is unclear. This study used homology-based gene identification methods to identify antimicrobial peptide genes from collembola genomes and transcriptomes. We analyzed five collembola species representing three main suborders and identified 45 antimicrobial peptide genes from five families: diapausin, Alo, diptericin, defensin, and cecropin. These peptides potentially have broad activity against bacteria, fungi, and viruses. This study highlights collembola as a new source for discovering novel AMPs that may help solve the current multidrug-resistant pathogen crisis. ABSTRACT: Multidrug-resistant bacteria are a current health crisis threatening the world’s population, and scientists are looking for new drugs to combat them. Antimicrobial peptides (AMPs), which are part of the organism’s innate immune system, are a promising new drug class as they can disrupt bacterial cell membranes. This study explored antimicrobial peptide genes in collembola, a non-insect hexapod lineage that has survived in microbe-rich habitats for millions of years, and their antimicrobial peptides have not been thoroughly investigated. We used in silico analysis (homology-based gene identification, physicochemical and antimicrobial property prediction) to identify AMP genes from the genomes and transcriptomes of five collembola representing three main suborders: Entomobryomorpha (Orchesella cincta, Sinella curviseta), Poduromorpha (Holacanthella duospinosa, Anurida maritima), and Symphypleona (Sminthurus viridis). We identified 45 genes belonging to five AMP families, including (a) cysteine-rich peptides: diapausin, defensin, and Alo; (b) linear α-helical peptide without cysteine: cecropin; (c) glycine-rich peptide: diptericin. Frequent gene gains and losses were observed in their evolution. Based on the functions of their orthologs in insects, these AMPs potentially have broad activity against bacteria, fungi, and viruses. This study provides candidate collembolan AMPs for further functional analysis that could lead to medicinal use.