Incidence and Distribution of Grapevine Leafroll-associated viruses in Tunisian Vineyards

摘要

Surveys were carried out in Tunisian table grape vineyards for assessing the occurrence and distribution of grapevine leafroll-associated viruses (GLRaVs). Leafroll symptoms were commonly observed in most of the surveyed vineyards. Samples were randomly collected from 712 individual vines for laboratory testing. Enzyme-linked immunosorbent assay (ELISA) tests showed that 81.5% of the vines were infected by one (35.7%) or more (45.8%) viruses. GLRaV-3 was the most widespread virus (76.3%), followed by GLRaV-5 (38.5 %), GLRaV-6 (13.2%), GLRaV-1 (9.1%), GLRaV-2 (6.3%), and GLRaV-7 (0.9%). GLRaV-3 and GLRaV-5, two mealybug-transmissible Ampeloviruses, were present in mixture in 35.9% of samples. The highest infection rate was found in Cape Bon region (81.7 %), where cv. Italia had an infection rate of 79.5%. Superior seedless, the main cultivar in Sidi Bouzid, had 75% infection. GLRaV-6 and -7 were detected for the first time in Tunisia.