First Detection of Rupestris stem pitting associated virus Particles by Antibody to a Recombinant Coat Protein

Rupestris stem pitting associated virus (RSPaV), a member of the genus Foveavirus, is associated with the Rupestris stem pitting component of the Rugose wood (RW) disease complex of grapevines. Heretofore, particles of RSPaV have not been visualized. In this work, flexuous rod particles approximately 723 nm in length were detected in the sap of infected grapevines by immunosorbent electron microscopy (ISEM), using a polyclonal antiserum produced to a recombinant coat protein of RSPaV. Particles of RSPaV were detected in tissue culture-, greenhouse-, and field-grown grapevines infected with RSPaV, but not in healthy control plants. Detection of virus particles by ISEM corresponded with detection of RSPaV by Western blot, enzyme-linked immunosorbent assay, and reverse transcription-polymerase chain reaction. Virus particles were decorated with the antibodies specific to RSPaV but not with antibodies to Grapevine virus A or Grapevine virus B, two other viruses believed to be associated with RW. This definitive identification of RSPaV particles will help define the etiology of RW.