Expressed sequence tags from the plant trypanosomatid Phytomonas serpens

We have generated 2190 expressed sequence tags (ESTs) from a cDNA library of the plant trypanosomatid Phytomonas serpens. Upon processing and clustering the set of 1893 accepted sequences was reduced to 697 clusters consisting of 452 singletons and 245 contigs. Functional categories were assigned based on BLAST searches against a database of the eukaryotic orthologous groups of proteins (KOG). Thirty six percent of the generated sequences showed no hits against the KOG database and 39.6% presented similarity to the KOG classes corresponding to translation, ribosomal structure and biogenesis. The most populated cluster contained 45 ESTs homologous to members of the glucose transporter family. This fact can be immediately correlated to the reported Phytomonas dependence on anaerobic glycolytic ATP production due to the lack of cytochrome-mediated respiratory chain. In this context, not only a number of enzymes of the glycolytic pathway were identified but also of the Krebs cycle as well as specific components of the respiratory chain. The data here reported, including a few hundred unique sequences and the description of tandemly repeated motifs and putative transcript stability motifs at untranslated mRNA ends, represent an initial approach to overcome the lack of information on the molecular biology of this organism.