In silico identification of off-target pesticidal dsRNA binding in honey bees ( Apis mellifera )

Background: Pesticidal RNAs silencing critical gene function have great potential in pest management, but the benefits of this technology must be weighed against non-target organism risks. Methods: . Published studies that developed pesticidal dsRNAs were collated into a database. The target gene sequences for these pesticidal RNAs were determined, and the degree of sequence homology with the honey bee genome were evaluated statistically for each. Results: . We identified 101 insecticidal dsRNAs sharing high sequence homology with genomic regions in honey bees. The likelihood of off-target sequence homology increased with the parent dsRNA length. Non-target gene binding was unaffected by taxonomic relatedness of the target insect to honey bees, contrary to previous assertions. Gene groups active during honey bee development had disproportionately high sequence homology with pesticidal RNAs relative to other areas of the genome. Discussion: Although sequence homology does not itself guarantee a significant phenotypic effect in honey bees, in silico screening may help to identify appropriate experimental endpoints within a risk assessment framework for pesticidal RNAi.