Wageningen Agricultural University, Department of Virology, Binnenhaven 11, 6709 PD Wageningen, the Netherlands
Using protein blot assays, a 94-kDa thrips protein was identified that exhibited specific binding to tomato spotted wilt virus (TSWV) particles. Renaturation of the 94-kDa protein, which is conserved among the two major vector species of TSWV, Frankliniella occidentalis and Thrips tabaci, was crucial for its virus-binding properties, whereas under the same conditions no specific binding was observed with aphid (Myzus persicae) proteins. The 94-kDa protein species was present in all developmental stages of both vectoring thrips, whereas it was present mainly in the adult stage of a nonvectoring thrips species, Parthenothrips dracenae. Using antibodies against the different TSWV structural proteins, the G2 envelope glycoprotein was identified as the viral determinant involved. Because the virus-binding protein is present throughout the thrips body, but not in the gut, it may represent a receptor protein involved during circulation of the virus through its vector but probably not during viral uptake in the midgut.