Development and testing of molecular strategies to thwart polerovirus transmission by aphids

Insect-vectored viruses pose one of the greatest threats to agriculture and subsequently human health. One virus, in particular, is the Potato leafroll virus (PLRV). It is a polerovirus, vectored by the green peach aphid, Myzus persicae, and infects solanaceous crops causing economically devastating symptoms. Transmission of poleroviruses depends on circulation through the aphid body regulated by specific, tri-trophic protein interactions between virus, vector, and plant. Currently, the molecular details of polerovirus acquisition/transmission and vector manipulation are lacking. Recent research from our group on the characterization and perturbation of a key interaction between a virion structural protein with the aphid gut reveals a potentially effective, biologically-based vector management strategy. We have solved the crystal structure of the PLRV structural protein (NRTD), which protrudes from the surface of the virion and is a key protein for aphid transmission of poleroviruses. We are exploring the NRTD as a tool to decrease the transmission of PLRV. We designed virus acquisition and transmission bioassays and showed the NRTD's potential for virus transmission blocking. We developed transgenic potato plants consecutively expressing the yellow fluorescent protein (YFP) fused to the N-RTD. Oral delivery of NRTD to aphids via expression in plants reduces virus transmission by aphids in greenhouse-grown potato plants, and reduces viral load in the aphids when quantified by digital PCR. Our ongoing experiments focus on testing whether N-RTD-expressing transgenic plants can protect wild-type potatoes in a large hoop house from PLRV transmission with potential commercial applications for controlling aphids and the viruses they transmit.