Transcript Analysis of Sedentary Female Reniform Nematodes Identifies Potential Targets for RNAi-mediated Resistance

RNA-interference (RNAi) has become an attractive avenue of research in the development of crop resistance to sedentary plant-parasitic nematodes.  A prerequisite for this type of research is the availability of high quality gene sequence data for the nematode in question.  The reniform nematode (Rotylenchulus reniformis) is a damaging pest of Upland cotton that may be vulnerable to an RNAi-based control strategy; however, there is currently an extremely limited amount of gene sequence data available for this pest.  In this report, we describe the construction and analysis of a cDNA library that was created using total RNA isolated from sedentary female reniform nematodes.  A total of 2,784 cDNA clones were sequenced which produced 555 unique non-overlapping R. reniformis expressed sequence tags (ESTs).  Bioinformatic analyses of these ESTs identified >60 sequences that showed significant homology (P<1.0e-15) to Caenorhabditis elegans genes that present lethal phenotypes following RNAi.  A number of R. reniformis ESTs also showed homology to sequences derived from sedentary and migratory plant-parasitic nematodes and some animal parasites.  The details of these analyses and their implications for the development of RNAi-mediated reniform nematode resistance in cotton will be discussed.