Oral delivery of dsRNA to potato psyllid (Bactericera cockerelli) via sachet

The potato/tomato psyllid, Bactericera cockerelli (B. cockerelli) is a vector of phloem-limited bacterium that can be linked to a plant disease in potatoes called Zebra chip. Zebra chip is associated with Candidatus liberibacter solanacearum a gram negative bacteria that causes millions of dollars in crop damages every year. We used B. cockerelli sequences to identify potential targets for RNA interference via oral delivery of double stranded RNA to induce mortality in test samples of live psyllids feeding in sachets. CDNA libraries were prepared by analyzing sequences using Geneious to assemble into contigs and then limited to primer design in the 500-1000 bp amplicons. These primers were screened with B. cockerelli DNA amplification and those that were successful were amended with the T7 promoter on the 5' end and re screened. Successful T7 primers were then converted into dsRNA using a MEGAscript RNAi kit and placed into sachets with trial psyllids. Mortality was measured on a 96 hour basis and recorded. Trials are ongoing, however we hope these results conclude that RNA interference can be a useful tool for the control of B. cockerelli populations and limit the exposure of these plants to the pathogen.