The mitochondrial genome characteristics of Coronocyclus coronatus (Looss, 1900) and comparative analysis with other strongylid nematodes.

Abstract

As important equine parasites, strongylid nematodes can cause severe health impairments and economic losses in the livestock industry. Current control strategies primarily rely on anthelmintic drugs. Therefore, elucidating the characteristics of its mitochondrial genomes not only clarifies the evolutionary mechanisms of strongylid nematodes but also provides a molecular-level theoretical basis for developing environmentally adaptive control strategies. In this study, the complete mitochondrial genome of Coronocyclus coronatus was sequenced and analyzed using next-generation sequencing technology. Results revealed a 13,870 bp circular double-stranded molecule containing 12 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and 2 non-coding regions, with a high AT content (74.75%) indicating significant AT bias. Among the 12 protein-coding genes, ATT, TTG, and ATA served as start codons. All genes terminated with complete TAA or TAG stop codons, except for COX3 which used an incomplete T stop codon. Phylogenetic analysis revealed closer affinity of C. coronatus with Cylicocyclus than with other Coronocyclus species. This study enriches mitochondrial genome data for strongylid nematodes, providing a foundation for resolving the taxonomic status and molecular evolution of Strongylidae.