John L. Sherwood, PhD, University of Georgia

The Sherwood laboratory is focused on the acquisition of the tomato spotted wilt tospovirus (TSWV) by its thrips vector. TSWV is only transmitted by thrips when it is acquired during the larval stage. The virus replicates in thrips so the vector may transmit the virus for its entire life. The lab has documented that the membrane glycoproteins (GPs) of TSWV bind a 50 kDa protein present in larvae of the western flower thrips (WFT), Frankliniella occidentalis (Pergande)]. Furthermore, the lab found that anti-idiotypic antibodies that mimic the TSWV GPs specifically label midgut membranes of larval WFT. They hypothesize that one or both of the TSWV GPs serve as viral attachment proteins (VAP) that interact with one or more cellular receptors (CRS) in the WFT midgut to mediate virus acquisition. This hypothesis is consistent with mechanisms of virus acquisition described for mosquito transmitted membrane-bound viruses of vertebrates in which the fidelity of virus acquisition relies on the interaction between a VAP(s) and a corresponding CRS(s) in the vector. The specific mechanisms underlying virus acquisition for circulatively transmitted plant viruses are not well understood. Thus, the TSWV-WFT system provides a model for molecular characterization of acquisition of a membrane-bound plant-infecting virus by its insect vector which should provide information to develop controls for diseases caused by TSWV.

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