The efficiency of RNA interference in Bursaphelenchus xylophilus

RNA Interference (RNAI) was performed on several essential genes in the pinewood nematode Bursaphelenchus xylophilus, which causes pine wilt disease. Double-stranded RNA (deRNA) was delivered to larvae or adult worms by soaking, electroporation, or microinjection. Soaking and electroporation of L2-L3 stage worms in solutions containing dsRNA for essential genes Induced over 250% lethality after 5 days, and gene-specific phenotypes were observed. This lethality agreed with significant reductions of the targeted transcripts, as assayed by reverse-transcription coupled with real time PCR. Microinjection was the most efficient routs as measured by the hatching rate of F1 embryos, which was reduced by 46%. When adult worms were soaked In dsRNA, lethality was induced in the F1 larvae, revealing the persistence of knockdown phenotypes. The penstrance of the RNA/phenotypes for essential genes was relatively low but consistent indicating that RNA/ should be useful for studying the in vivo functions of B. xylophilus gene products.