Eimeria tenella: Analysis of differentially expressed genes in the monensin- and maduramicin-resistant lines using cDNA array

Drug resistance in coccidial populations has been a major problem to the prophylactic chemotherapy. Nevertheless, the mechanisms of the resistance are still poorly understood. In this report, cDNA array was designed based on the cDNA library for analysis of gene expression profile of the drug-resistant lines and their sensitive parental lines of Eimeria tenella. Two thousand eight hundred and six ESTs (expressed sequence tags) were obtained from 9600 clones which were randomly derived from the cDNA library with the 3′ end sequencing. A total of 1424 TUTs (tentative unique transcripts) were determined from the database of our ESTs by bioinformatics analysis, from which a cDNA array was developed. The comparison of monensin-resistant line (MonR) and maduramicin-resistant line (MadR) with their sensitive parental lines was undertaken independently. It was observed that the number of the up-regulated genes was 5.58-fold more than that of the down-regulated genes in MonR when compared with its parental line. The up-regulated genes were mainly involved in cytoskeletal rearrangements and energy metabolism. In MadR, the number of the down-regulated genes was 3.07-fold more than the up-regulated genes, which were mainly related to invasion and cytoskeletal genes. However, in MadR the level of the glycometabolism-related and potential transporter genes were reduced. Our data suggest that the mechanisms of monensin and maduramicin resistance of E. tenella might be a very complex process.