First report of Tomato infectious chlorosis virus from tomato in Apulia, southern Italy

A severe disease of tomato was observed in 2010 in a greenhouse in the province of Lecce (Apulia, southern Italy). Plants showed interveinal yellowing and thickening of mature leaves and a bushy appearance of the new growth. Pale-yellow spots, which became sunken and necrotic, were scattered on the fruit surface. Leaf symptoms were reminiscent of those induced by Tomato chlorosis virus (ToCV) or Tomato infectious chlorosis virus (TICV), while fruit symptoms recalled those of Tomato spotted wilt virus (TSWV). Symptomatic leaf tissues and fruits collected from six tomato plants cv. Genio were analysed by dot blot hybridization (Saldarelli et al., 1996) using DIG-labelled DNA probes of the Agritest tomato kit (Agritest, Italy) specific for the following viruses: Alfalfa mosaic virus (AMV), Cucumber mosaic virus (CMV), Pelargonium zonate spot virus (PZSV), Pepino mosaic virus (PepMV), Potato virus X (PVX), Potato virus Y (PVY), Tobacco mosaic virus (TMV), TICV, ToCV and TSWV. In two of the six samples a mixed infection of TICV and TSWV was detected, whereas only TSWV was present in the remaining samples. TSWV but not TICV was transmitted to tomato cvs UC82, Faino, Diaz, and Messapico by mechanical inoculation using extracts from thin slices of fruit epidermis cut near the necrotic areas. All tomato cultivars became infected systemically suggesting that the TSWV isolate was of the resistance-breaking type (Ciuffo et al., 2005). TICV has been recorded from tomato and artichoke in different Italian regions (Liguria, Sardinia, Latium, Campania and Sicily) but not from Apulia. Its presence in mixed infection with TSWV suggests that some synergistic interaction may occur to facilitate plant invasion, as reported for ToCV and TSWV (García-Cano et al., 2006).