RNA interferance: Potato/tomato psyllid, Bactericera cockerelli, oral delivery of double–stranded RNAi constructs

The potato/tomato psyllid, Bactericera cockerelli, is a serious and economically important pest of the potato, tomato and other solanaceous crops. This insect is the putative primary vector of the phytopathogenic bacterium Candidatus Liberibacter psyllaurous (solanacearum) which causes the Zebra Chip of potato. This disease has caused millions of dollar loss to the potato industry. Management of this pest by down-regulation of endogenous mRNA using RNAi technology is possible. In this study, we have studied the downregulation of certain targeted genes of potato psyllid by RNA interference (RNAi) induced gene silencing technology. We targeted certain potential genes to be downregulated that codes for Actin, alpha- tubulin and beta – tubulin, yellow B, integrin, gelsolin and ribosomal proteins. Thirty teneral adult psyllids were offered sachet that contains artificial diets amended with dsRNA (RNAi constructs) and monitored for ten days. To determine if selected dsRNAs crossed the gut barrier and enter the hemolymph, fluorescently labeled dsRNA probes were used to document the presence of dsRNA in the hemolymph and to the different organs. Individual psyllids were dissected and the presence of labeled probe in the specific tissue was identified by PCR and visualized by fluorescence microscopy.