Effects of ced-9 dsRNA on Caenorhabditis elegans and Meloidogyne incognita

Abstract: Problem Statement: In metazoans Programmed Cell Death (PCD) is essential for proper development. Suppression of PCD is needed to guarantee cell survival and in the nematode Caenorhabditis elegans the regulation of PCD is accomplished by the function of the ced-9 gene. Approach: In this work the use of double stranded RNA (dsRNA) to knock-down ced-9 gene function was tested as means to induce PCD. Results: Our results indicate that dsRNA targeting the cell death protection gene ced-9 is effective at decreasing the fecundity of C. elegans by up to 21%. The decreased fecundity correlated with an increased presence of cell corpses in developing embryos. Endogenous ced-9 transcript levels were reduced in progeny of ced-3 mutant nematodes fed bacteria expressing ced-9 dsRNA. These data suggest that nematode fecundity can be reduced by ingestion and exposure to dsRNAs targeting regulation of the cell death pathway. In an attempt to determine if plant parasitic nematodes are susceptible to the targeting of the PCD regulatory pathway we exposed Meloidogyne incognita, a plant parasitic nematode, to ced-9 dsRNA; here we show that this exposure results in decreased gall formation in the tobacco plants. Conclusion/Recommendations: Our results provide the first steps toward using RNAi technologies to attempt nematode control by targeting cell death pathways. Ongoing research with transgenic plants designed to express dsRNA for ced-9-like sequences will further test the feasibility of generating plants with RNAi-based resistance to parasitic nematodes.