Transcript analysis of parasitic females of the sedentary semi-endoparasitic nematode Rotylenchulus reniformis

Rotylenchulus reniformis, the reniform nematode, is a sedentary semi-endoparasitic nematode capable of infecting >300 plant species, including a large number of crops such as cotton, soybean, and pineapple. In contrast to other economically important plant-parasitic nematodes, molecular genetic data regarding the R. reniformis transcriptome is virtually nonexistant. Herein, we present a survey of R. reniformis ESTs that were sequenced from a sedentary parasitic female cDNA library. Cluster analysis of 2004 high quality ESTs produced 123 contigs and 508 singletons for a total of 631 R. reniformis unigenes. BLASTX analyses revealed that 39% of all unigenes showed similarity to known proteins (E ≤ 1.0e−04). R. reniformis genes homologous to known parasitism genes were identified and included β-1,4-endoglucanase, fatty acid- and retinol-binding proteins, and an esophageal gland cell-specific gene from Heterodera glycines. Furthermore, a putative ortholog of an enzyme involved in thiamin biosynthesis, thought to exist solely in prokaryotes, fungi, and plants, was identified. Lastly, 114 R. reniformis unigenes orthologous to RNAi-lethal Caenorhabditis elegans genes were discovered. The work described here offers a glimpse into the transcriptome of a sedentary semi-endoparasitic nematode which (i) provides the transcript sequence data necessary for investigating engineered resistance against R. reniformis and (ii) hints at the existance of a thiamin biosynthesis pathway in an animal.