Senescent Eimeria acervulina oocysts maintain transcriptional activity during extended refrigerated storage and differerntially express characteristic genes

Infectious, sporulated parasites eventually senesce. Here, we examined transcriptional changes in sporulated oocysts of Eimeria acervulina stored for 4-30 months at 4°C. Precipitous decline in RNA abundance and transcription followed an interval of stability.

Sixty constitutively expressed genes each contributed >1,000 transcripts per million (TPM) throughout, including a serine protease inhibitor, surface antigen genes, a cation-transporting ATPase, an oocyst wall protein, a zinc finger DHHC domain-containing protein, and highly expressed hypothetical proteins with no known function. Strikingly, ~82% of 6,867 annotated genes underwent differential expression when comparing freshly sporulated parasites to those held for 30 months; nearly one-third of these underwent significant expression change.