Transcriptomic analysis and screening of target genes for RNAi mediated control of cigarette beetle, Lasioderma serricorne.

The cigarette beetle (Lasioderma serricorne) is a stored product pest, especially on stored tobaccoproducts. Fumigation is the common control method currently used. However, the options forcontrolling this pest are limited, due to the development of resistance and phasing out of currentlyused chemical insecticides. Here, we evaluated RNA interference (RNAi) as a potential method forcontrolling the cigarette beetle. RNA isolated from different stages was sequenced and assembled intoa transcriptome. The cigarette beetle transcriptome sequences showed the highest homology withthose in Tribolium castaneum. Homologs of proteins known to function in RNAi were found in thecigarette beetle transcriptome, suggesting that RNAi may work well in this insect. Also, 32P labeleddsRNA injected into the cigarette beetle larvae and adults was processed to siRNA. We selected 12genes that were shown to be the most effective RNAi targets in Tribolium castaneum and other insectsand identified homologs of them in the cigarette beetle searching the transcriptome. Injection ofdsRNA targeting genes coding for GAWKY, Kinesin, Sec23, SNF7, and 26S proteasome subunit 6Binto the cigarette beetle larvae caused close to 100 % mortality. Feeding of dsRNA targeting SNF7and 26S proteasome subunit 6B sucrose drop assay induced mortality over 90%. Our results showefficient RNAi response in the cigarette beetle and therefore, RNAi can be developed as an efficientmethod to control this pest.