An rhabdovirus

An rhabdovirus incompletely characterized .

In recent years, symptoms observed on lettuce seed carriers, grown in France in the Rhône valley, have been associated with the presence of a rhabdovirus. Particles could be observed directly by electron microscopy in the lettuce extracts. On affected plants, yellow mottling in fairly large spots could be observed. On some varieties, small yellow macules, more or less angular, were irregularly distributed around the edges of the leaves.
The incriminated virus could be transmitted experimentally, by mechanical inoculation, to a small range of hosts including some tobacco species, petunia, Datura stramonium and Physalis floridana . Cytopathology studies have made it possible to localize the virus in the cytoplasm, in vesicles of the endoplasmic reticulum: it is therefore a Cytorhabdovirus .

Two Cytorhabdoviruses have already been described in the literature as being able to infect lettuce: Lettuce necrotic yellow virus (LNYV), present exclusively in Australia and New Zealand, and Sonchus virus (SV), isolated in Argentina. On the basis of the symptoms observed on lettuce and on the host range, the virus isolated in France would approach SV. The main characteristics of LNYV can be seen in the sheet above. The vectors of SV are not known.

The characterization of this rhabdovirus isolated in France will require additional studies.