1. Analytical Equipment Unit, Ben-Gurion University of the Negev, Beer-Sheva, Israel
2. Department of Plant Pathology, The Institute of Plant Protection, Agricultural Research Organization, Gilat Experiment Station, M.P. Negev, Israel
3. Department of Virology and Developmental Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel