Mixed infection of black currant (Ribes nigrum L.) plants with Blackcurrant reversion associated virus and rhabdovirus-like particles with symptoms of black currant reversion disease.
Black currant plants of cvs. Black Smith and Karlstejnský dlouhohrozen showing symptoms of severe Russian (R) form of black currant reversion disease (BCRD) were found in 1999-2000 in the Czech Republic. Five selected plants of both cultivars originating from two distant loci were tested by polymerase chain reaction (PCR) for presence of the Blackcurrant reversion associated virus (BRAV), the causal agent of BCRD. In all plants, virus-specific 215 nt cDNA fragments proving the presence of BRAV were obtained. Moreover, in two of those five black currant plants, rhabdovirus-like particles were found in ultrathin sections by electron microscopical examinations. The particles measured 200-347 nm by 64-90 nm. They occurred mostly within nuclei of parenchyma cells of vascular bundles as single particles, rafts of particles, but also in aggregates. They were found also in the perinuclear space and occasionally directly in the cytoplasm. Clusters of particles either within the nucleus or in the perinuclear space were membrane-bound. We bring evidence on the occurrence of the severe (R) form of BCRD and the first evidence of BRAV in the Czech Republic.