First report of Eggplant mottled dwarf virus in potato and tomato in Slovenia

In June 2004, potato plants of cvs. Bistra, Desiree, Discovery, KIS94-1/5-14 and PÅ¡ata, showing unusual virus-like symptoms, were observed in a field in central Slovenia. Crops from different parts of the country were planted in this field to compare the frequency of virus infections. The symptoms were observed only on potatoes originating from Rakičan in north-eastern Slovenia. Symptomatic plants showed severe dwarfing, leaf curling and reduced leaf size; tubers were very small and few in number. Brown spots were clearly visible in cross sections of tubers. Sap of symptomatic plants was used for mechanical inoculation of test plants. Local and systemic symptoms were observed on Nicotiana benthamiana, N. clevelandii, N. glutinosa, N. rustica, N. tabacum, but only local lesions on Datura stramonium. No symptoms were observed on Chenopodium quinoa. Electron microscopy of negatively stained crude extracts from symptomatic N. benthamiana, N. clevelandii and N. tabacum revealed numerous rhabdovirus-like particles.

During summer of 2003 tomato plants cv. Belle, showing unusual symptoms of distinct chlorotic spots, wrinkles on fruits and narrow, necrotic leaves, were observed in north-eastern Slovenia, about 16 km from Rakičan. Infected plants also showed size reduction, curling of mature leaves, yellowing and chlorosis along the margins of younger leaves. Electron microscopy of negatively stained crude extracts revealed rhabdovirus-like particles. Three weeks after mechanical inoculation with extracts from symptomatic leaves, systemic yellowing of veins and leaf curling was observed on N. tabacum cv. White Burley and necrotic spots, starting on the bases of the leaves on N. clevelandii. These symptoms resembled those of potato isolate. Electron microscopy of crude sap extracts again revealed rhabdovirus-like particles.

DAS-ELISA was used for confirmation of rhabdovirus infection of potato, tomato, symptomatic N. rustica infected with potato sap and symptomatic N. tabacum cv. White Burley infected with tomato sap. Antisera against Eggplant mottled dwarf virus (EMDV) and Potato yellow dwarf virus (PYDV) were kindly supplied by Dr. S. Winter, DSMZ, Braunschweig, Germany. ELISA results confirmed infection of tested plants with EMDV. No infections with PYDV were found. EMDV is widespread in the Mediterranean region and the Middle East (Brunt et al. 1996), and has recently been reported in mainland Spain (Aramburu et al., 2005). To our knowledge this is the first report of EMDV in Slovenia.