New virus associated with blackcurrant reversion disease
Blackcurrant reversion disease is a virus-like disease, transmitted by the eriophyid gall mite Cecidophyopsis ribis. The disease is present in all countries where blackcurrant (Ribes nigrum) is grown commercially (except the Americas) and presents at least two forms according to symptoms, the common form and a more severe form. Blackcurrant reversion disease is not a quarantine pest for EPPO, but it has to be addressed in certification schemes for the production of healthy planting material of Ribes. The causal agent of this disease was unknown. But recent studies carried out in Finland and Scotland have shown that a new virus associated with reverted blackcurrant plants, probably a nepovirus, might be the causal agent. This virus was mechanically transmitted with difficulty from a blackcurrant plant affected by the severe form of the disease to Chenopodium quinoa and then to other herbaceous test plants. The virus was purified, partially characterized, and a PCR test was developed. This virus was detected in blackcurrant plants showing symptoms of the disease (both the common and severe ones). It was also found in vector gall mites from reverted plants and in plants where such vector mites had fed. But it was not detected on healthy blackcurrants or plants affected by other diseases. Although, Koch’s postulates could not be fully verified, the virus is tentatively called blackcurrant reversion associated virus.
Lemmetty, A.; Latvala, S.; Jones, A.T.; Susi, P.; McGavin, W.J.; Lehto, K. (1997) Purification and properties of a new virus from black currant, its affinities with nepoviruses and its close association with black currant reversion disease.