Transcriptome analysis of the adult rumen fluke Paramphistomum cervi following next generation sequencing.

Rumen flukes are parasitic trematodes (Platyhelminthes: Digenea) of major socioeconomic importance in many countries. Key representatives, such as Paramphistomum cervi, can cause "Rumen fluke disease" or paramphistomosis and undermine economic animal productivity and welfare. P. cervi is primarily a problem in sheep, goat and buffalo production as a consequence of reduced weight gain and milk production, clinical disease or death. Recent technological advances in genomics and bioinformatics now provide unique opportunities for the identification and pre-validation of drug targets and vaccines through improved understanding of the biology of pathogens such as P. cervi and their relationship with their hosts at the molecular level. Here, we report next generation transcriptome sequencing analysis for P. cervi. RNAseq libraries were generated from RNA extracted from 15 adult P. cervi parasites sampled from each of three different host species (sheep, goat and buffalo) and a reference transcriptome was generated by assembly of all Ion Torrent PGM sequencing data. Raw reads (7,433,721 in total) were initially filtered for host nucleotide contamination and ribosomal RNAs and the remaining reads were assembled into 43,753 high confidence transcript contigs. In excess of 50% of the assembled transcripts were annotated with domain- or protein sequence similarity derived functional information. The reference adult P. cervi transcriptome will serve as a basis for future work on the biology of this important parasite. Using the widely investigated trematode virulence factor and vaccine candidate Cathepsin L as an example, the epitope GPISIAINA was found to be conserved in P. cervi isolated from three different host species supporting its candidacy for vaccine development and illustrating the utility of the adult P. cervi transcriptome.