An unidentified 50 kDa protein is a candidate receptor for tomato spotted wilt tospovirus (TSWV, Bunyaviridae) in its main vector, the western flower thrips, Frankliniella occidentalis Pergande. To identify, clone and characterize the TSWV receptor we constructed a thrips cDNA expression library and screened for virus-binding polypeptides by a far-Western assay. Sequence analysis revealed that all selected clones have four motifs in common with beta integrins [the hantavirus (Bunyaviridae) receptors], which indicates structural similarity and evolutionary implications. One of the clones (TR313) is expressed at high levels in larvae (susceptible stage) but at poor levels in adults (resistant stage), shares homology with an arylphorin receptor, localizes in the guts (receptor expected site) and anti-TR313 antibody inhibited TSWV infection of thrips tissues. These data indicate that TR313 is the TSWV receptor in thrips cells.

Index terms: Frankliniella occidentalis, virus vector, Tospovirus.

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