Chromosomal scale assembly and functional annotation of the apicomplexan parasite Eimeria acervulina.

Apicomplexan parasites are single-celled obligate intracellular eukaryotic organisms that cause significant animal and human disease and pose a substantial health and socioeconomic burden worldwide. Eimeria acervulina is one such parasite of chickens, representative of several Eimeria species causing coccidiosis disease. A complete assembly of the E. acervulina genome may help identify markers of drug-resistance and design recombinant vaccines. We sequenced E. acervulina APU1 strain using Oxford Nanopore Sequencing and Illumina technology in combination with a Hi-C (Omni-C) proximity linkage library and achieved a chromosomal scale assembly using the MaSuRCA assembler. The final assembly was 52 Mb. with 15 chromosomes and 99% BUSCO completeness. A total of 7,621 genes were predicted using a pipeline of BRAKER3, GeneMark-ETP and AUGUSTUS, of which 4,647 (60.97%) have a predicted Pfam function and 1,962 (25.74%) have Gene Ontology (GO) terms matching molecular, biological, and functional classes. Stage-specific transcriptome analysis revealed 9,761 transcripts. This genome assembly and transcriptome analysis provides the foundation for identifying biologically important candidates for anticoccidial drug and vaccine development.