A strain of Holmes' ribgrass virus occurring in Yugoslavia

A virus having 300 nm long rod-shaped particles was isolated fromPlantago media L. in Yugoslavia. The virus was transmitted to 15 species of host plants the symptoms of which are described in detail. The symptoms corresponded to those that appeared after infection by the original Holmes' ribgrass virus (HRV). The investigated virus was compared both with the common strain of tobacco mosaic and the original Holmes' ribgrass viruses by means of serological tests. The agar double-diffusion tests showed that it is closely related to HRV and remotely related to the common strain of TMV. On the basis of these results we concluded that this virus represented a strain of the HRV. The investigations of the cell inclusions showed that our virus produced rounded plates instead of hexagonal prisms. Electron micrographs of ultrathin sectioned material demonstrated that these plates were formed by virus particles lying perpendicularly to the layers of the plates. The presence of plates also points to the fact that the investigated virus belongs to the HRV.