Assessing geminiviruses prevalence in Mediterranean vegetable crops

One of the most harmful viruses to vegetable crops, especially in the Mediterranean Basin, is the family Geminiviridae known as the "geminivirus." A project on the prevention and control of new and invasive geminiviruses infecting vegetables in the Mediterranean was launched through an international 3-year collaboration federated by a PRIMA call (Partnership for research and innovation in the Mediterranean area). This project involved public and private institutions from Italy, Jordan, Tunisia, Morocco, and France. Virus-specific PCR tests on DNA extracted from symptomatic tomato and cucurbit plants have been used to monitor the prevalence of geminiviruses previously described in this region, including tomato yellow leaf curl associated viruses, tomato leaf curl New Delhi virus, chickpea chlorotic dwarf virus, squash leaf curl virus, and watermelon chlorotic stunt virus. Meanwhile, deep sequencing of DNA extracted from insects collected in the surveyed areas (mainly whiteflies, aphids, and leafhoppers) is being used to look into the possibility of novel geminiviruses circulating in the region. To compare results of viral incidence between countries, standardized procedures for collecting, preserving, and analyzing leaf and insect samples have been established. In different agroecosystems in the following countries in 2020-2021, more than a thousand leaf samples and about 200 insect samples were collected: Morocco, in the Berkane area in the North-East and Souss region in the South; Tunisia, in the Center, North, and Sahel regions; Italy, in Campania and Sicily; and the Northern area of Jordan. These surveys are being used to update data on geminivirus prevalence across the Mediterranean Basin.