Abstract
Analyses of transcriptomic datasets have the potential to reveal genetic markers underlying ecological adaptations. In the present study, we leverage the expanding dataset generated by the Fish-T1K Project (Transcriptomes of 1000 Fishes) to characterize small peptides that may be implicated in the immune system of fishes. We focused our analyses on sequences smaller than 360 bp obtained from gill transcriptomes of 87 ray-finned fishes (Actinopterygii). Functional annotation of short transcripts revealed that the number of small immune peptides varied significantly among the studied species. High-throughput screening of antimicrobial peptides (AMPs) with homologous searches was used to characterize the composition of innate immune defense factors present in fishes. We analyzed the putative effects of habitat, climatic zone and genetic system on the distribution of small peptides among species. Our results highlight the utility of large transcriptomic datasets such as Fish-T1K to explore patterns of variation at macroevolutionary scales and to discover novel peptides that may be used for further investigation and drug development.
•The Fish-T1K, a big-data-based transcriptome database, allows for high-throughput identification of small peptides.•Gill transcriptomes of 87 Actinopterygii species were employed to search for short nucleotide sequences.•The numbers of small immune peptides and antimicrobial peptides varied remarkably among fishes in different habitats.•Our high-throughput approach offers a new way for exploration of novel active peptides and drug development.