Double-stranded RNA synthesized in bacteria can be transferred to bee and varroa tissues

In Argentina, the ectoparasite Varroa destructor and deformed wing virus (DWV) causes serious losses in local beekeeping. New control methods have been proposed based on the RNA interference technique. Previous reports showed that bees fed with double-stranded RNA (dsRNA) synthesized in vitro reduce the transcription levels of the target genes in DWV and the varroa mite. An efficient and inexpensive alternative to produce dsRNA is the use of bacteria capable of achieving a high level of in vivo synthesis. In this work, the possibility to use bacteria-mediated delivery of dsRNA to bees and varroa tissues was evaluated. The obtained results indicated that bacterially expressed dsRNA can be transferred to the bee and from bee to the varroa mite.