Bacterially Expressed dsRNA induces Varroa destructor gene knockdown by honey bee-mediated oral administration

RUSSO, ROMINA MARÍA; SALVADOR, RICARDO; LIENDO, MARÍA CLARA; NIZ, JOSE MARIA; MUNTAABSKI, IRINA; SCANNAPIECO, ALEJANDRA CARLA

Conferencia; 17th COLOSS Conference; 2021

The ectoparasite Varroa destructor causes serious losses of Apis mellifera colonies andnegatively impacts on the beekeeping industry around the world. New control methodshave been proposed based on the RNA interference technique. Previous reports showedthat parasitized honey bees fed with double-stranded RNA (dsRNA) synthesized in vitroreduce the transcription levels of target genes in Varroa mites. An efficient andinexpensive alternative to produce dsRNA is the use of bacteria capable of achievinghigh levels of in vivo synthesis. In the present study, dsRNA synthetized in vivo wasused to induce gene silencing in V. destructor and evaluate their effect on survival ofboth honey bees and the parasitic Varroa mites. The results evidenced that dsRNA fedto the bees engendered gene silencing in mites, inhibiting expression levels of targetgenes by approximately 50%. Indeed, a reduction of 50% on Varroa survival wasobserved when bacterially expressed dsRNAs were administered to mite-parasitizedbees. Worker bees that were fed with Varroa-targeted dsRNA by oral route showed nosurvival differences compared to control bees, fed with sucrose solution. Our resultsdemonstrated that specific dsRNA over-expressed in bacteria is capable of reducingmite survival by bee-mediated oral administration. This study provides an efficient andlow-cost method for dsRNA production to control parasites and honey bee diseases.