Master of Science
Insecticide resistance is often linked to the expression of detoxification genes such as MDRs which code for ATP-binding cassette efflux transporters with broad substrate specificity. To investigate the role of MDR genes in Leptinotarsa decemlineata and Trichoplusia ni tolerance for the insecticide ivermectin, ingested dsRNA was used to attempt silencing of various MDR genes in these insects through RNA interference. Silencing was effective in L. decemlineata, but not T. ni. No change in ivermectin tolerance was found in L. decemlineata after MDR gene silencing. Because RNAi efficiency was different between L. decemlineata and T. ni, the stability of dsRNA in midgut lumen and hemolymph was compared between the two species and another insect, Manduca sexta. The dsRNA was least stable in T. ni body fluids, providing a likely cause for the ineffectiveness of ingested dsRNA.
Favell, Grant, "RNA Interference of MDR Genes in Leptinotarsa decemlineata and Trichoplusia ni by Ingestion of Double-Stranded RNA" (2018). Electronic Thesis and Dissertation Repository. 5251.