Improved 18S and 28S rDNA primer sets for NGS-based parasite detection

The development and application of next-generation sequencing (NGS) have enabled comprehensive analyses of the microbial community through extensive parallel sequencing. Current analyses of the eukaryoticmicrobial community are primarily based on polymerase chain reaction amplification of 18S rRNA gene (rDNA) fragments. We found that widely-used 18S rDNA primers can amplify numerous stretches of the bacterial 16S rRNA gene, preventing the high-throughput detection of rare eukaryoticspecies, particularly in bacteria-rich samples such as faecal material. In this study, we employed in silico and NGS-based analyses of faecal samples to evaluated the existing primers targeting eukaryotic18S and 28S rDNA in terms of avoiding bacterial read contamination and improving taxonomic coverage for eukaryotes, with a particular emphasis on parasite taxa. Our findings revealed that newly selected primer sets could achieve these objectives, representing an alternative strategy for NGS.