Successful back-inoculation confirms the role of black currant reversion associated virus as the causal agent of reversion disease

Reversion is the most wide-spread and serious virus-like disease infecting black currant but the causal agent of the disease has not been described. R ecently, we have isolated a new nepovirus from reversion-infected black cur rant and by using immunocapture-RT-PCR detection, we have shown that the vi rus is consistently associated with reversion disease (Lemmetty et al., Phy topathology 87: 404-413, 1997). These data suggested that the virus, tentat ively called black currant reversion associated virus (BRAV), could be the causal agent of reversion disease. Here we report that the isolated virus w as successfully inoculated back to healthy black currant plants by slash in oculation of in vitro propagated young recipient plants. Vein pattern sympt oms identical or very similar to the reported early symptoms of reversion d isease were produced in the virus-infected plants. Using immunocapture-RT-P CR, the virus was again detected from symptomatic but not from inoculated s ymptomless plants or from the mock-inoculated or uninoculated controls. Pro duction of the acute reversion symptoms demonstrates that BRAV is the causa l agent of reversion disease, and we therefore propose that the virus be na med black currant reversion virus, abbreviated BRV.