Coat protein of a whitefly-vectored plant virus as a delivery system to target whitefly

The sweet potato whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) is responsible for significant crop losses and presents one of the greatest challenges for global agricultural pest management. Management of whitefly populations and associated plant viral diseases is hindered by widespread whitefly resistance to chemical insecticides. An alternative control approach involves the use of insect-specific neurotoxins, but these require delivery from the whitefly gut into the haemocoel. Here we demonstrate that the coat protein (CP) of a begomovirus, Tomato yellow leaf curl virus, is sufficient for delivery of fused proteins into the whitefly haemocoel without virion assembly. Following feeding on the recombinant CP-P-mCherry fusion (where -P- is a proline-rich linker), mCherry fluorescence was detected in the dorsal aorta and pericardial cells of the whitefly, but not in those of whitefly fed on negative control treatments, indicating effective CP-mediated delivery of mCherry into the whitefly haemocoel. Significant mortality was observed in whiteflies fed on a fusion of CP-P to the insect-specific neurotoxin Hv1a, but not in whiteflies fed on CP-P fused to a disarmed Hv1a mutant. Begomovirus coat protein - insect neurotoxin fusions hold considerable potential for transgenic resistance to whitefly providing valuable tools for whitefly management. Whiteflies pose a significant threat to agriculture particularly through their transmission of plant viral disease. Insect-specific neurotoxins provide a relatively untapped resource for pest management but require delivery from the whitefly gut into the body cavity. Here we demonstrate that the coat protein of a begomovirus, Tomato yellow leaf curl virus is sufficient for delivery of fused proteins into the whitefly hemocoel and demonstrate significant whitefly mortality following ingestion of a coat protein-neurotoxin fusion.image