COMPARTMENTALIZATION, INTRACELLULAR-TRANSPORT, AND AUTOPHAGY OF TOMATO SPOTTED WILT TOSPOVIRUS PROTEINS IN INFECTED THRIPS CELLS

Tomato spotted wilt tospovirus (TSWV) replicates in at least one of its thrips vectors, Frankliniella occidentalis. Viral proteins accumulate in cytoplasmic inclusions, but the location and composition of these inclusions have not been fully elucidated. Observations by electron microscopy of TSWV-infected thrips cells immunolabeled with antibodies to TSWV nucleocapsid protein (N), the membrane glycoproteins (G1 or G2), and the nonstructural protein encoded by the S RNA (NSs) indicated that TSWV encoded proteins were compartmentalized within viroplasms, dense masses, amorphous inclusions, and paracrystalline arrays. Amorphous inclusions have not been previously reported in TSWV infected tissues. Viral proteins were immunolocalized in structures known to be involved in intracellular transport and degradation of proteins including vesicles, putative autophagic vacuoles, and residual bodies. This is the first account of immunolocalization of TSWV-encoded proteins at intercellular membranes and membranes thought to be part of the Golgi complex.