Turnip mosaic virus infecting Eruca sativa in Sicily

In the Spring of 2010, Eruca sativa Mill. (Brassicaceae family), also known as rocket, cultivated in a private garden of Sicily region was found to show a severe virus-like disease consisting of mosaic, interveinal yellowing and/or dark greening areas on crinkled leaves and stunting. Preliminary electron microscopy observations of leaf-dips revealed the presence of flexuous filamentous particles 700-750 nm long. Considering that in 1959, in Italy, this species has been indicated as a natural host of Turnip mosaic virus (TuMV), symptomatic leaf samples were serological tested to verify the presence of this potyvirus. Both ISEM and PAS-ELISA analyses were positive to TuMV infection. Mechanical inoculations carried out using rocket leaf sap made it possible to transmit this virus to Chenopodium murale L. (local symptoms) and C. quinoa Willd. (necrotic spots and systemic veinal flecks); any of the others herbaceous species belonging to Brassicaceae family were infected. In order to further characterize the virus at the molecular level, the coat protein (CP) gene of this isolate was cloned and sequenced. These results indicated that the degrees of the homology of the CP genes are probably related to the major differences in host specificity, but not to geographic distribution. Although its diffusion in Italy, TuMV does not appears associated with serious diseases outbreaks.