The key glycolytic enzyme phosphofructokinase is involved in Eimeria tenella resistance to maduramycin.

The protozoan parasite Eimeria tenella causes coccidiosis in poultry, which results in substantial economic losses to the global poultry industry. Understanding the molecular mechanisms of drug resistance in E. tenella is essential for developing effective control strategies. The goal of this study was to investigate the role of E. tenella phosphofructokinase (EtPFK1) in mediating resistance to maduramycin, a widely used anticoccidial drug. Characterization of EtPFK1 expression across developmental stages and under drug treatment revealed elevated mRNA and protein levels in sporulated oocysts and maduramycin-resistant strains. Immunofluorescence assays showed its localization in the cytoplasm and on the surface of sporozoites. To elucidate the role of EtPFK1 in maduramycin-resistant strains, an EtPFK1-overexpressing strain was generated using the drug-sensitive strain of E. tenella. Overexpression of EtPFK1 reduced the sensitivity of E. tenella to maduramycin, as demonstrated by both in vitro and in vivo assays. Specifically, the EtPFK1-overexpressing strain exhibited complete resistance to 2 ppm maduramycin and light resistance to 5 ppm, indicating that EtPFK1 contributes to the development of drug resistance in E. tenella. Additionally, EtPFK1 overexpression reduced the pathogenicity of E. tenella, as demonstrated by fewer cecal lesions and lower oocyst output in infected chickens. EtPFK1 overexpression enhanced adaptation to high-glucose environments, potentially facilitating drug resistance. These findings highlight the multifaceted role of EtPFK1 in mediating drug resistance in E. tenella and provide insight into the development of novel therapeutic interventions against coccidiosis.