Submitted to: Plant Disease
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/11/2003
Publication Date: 11/11/2003
Citation: Petrovic, N., Meng, B., Ravnikar, M., Mavric, I., Gonsalves, D. 2003. First detection of Rupestris stem pitting associated virus particles by antibody to a recombinant coat protein. Plant Disease. 87:510-514. Interpretive Summary: Rupestris stem pitting is a widespread virus disease that manifests itself when infected material is graft-inoculated to the grapevine indicator 'St. George'. The Rupestris stem pitting associated virus is closely associated with the disease. Heretofore, the virus particles had not been visualized. Instead, the virus had been characterized by cloning and sequencing the double stranded RNA that is associated with the disease. In a recent publication, antibody was produced to virus coat protein that had been produced by expressing the coat protein gene in bacteria. In this work, we used the antibody in electron microscopy tests to visualize, for the first time, the Rupestris stem pitting associated virus particles in extracts of infected grapevines. These results provide the crucial evidence to link a defined virus particle to the Rupestris stem pitting disease of grapevines. This accomplishment should help in the further characterization of the virus particles and in the potential use of the antibody in combination with electron microscopy to rapidly screen grapevines for the presence of the virus.
Technical Abstract: Rupestris stem pitting associated virus (RSPaV), a member of the Foveavirus genus, 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.