First report of onion yellow dwarf virus, leek yellow stripe virus, and shallot latent virus on garlic (Allium sativum) in Tunisia.
The potyviruses onion yellow dwarf virus (OYDV) and leek yellow stripe virus (LYSV) are the most important viral pathogens of garlic (Allium sativum), whereas carlaviruses and allexiviruses seem to be less detrimental or even latent. In Tunisia, growers propagate self-produced garlic cloves and/or those from other farmers without phytosanitary control, which facilitates virus transmission. To determine the virus profile of garlic in Tunisia, 33 garlic accessions were collected from major garlic-growing regions and grown in the research farm of the High Agronomic Institute of Chott Mariem. In total, 66 plants (two per accession) were tested for potyviruses and carlaviruses. Ninety percent of leaf samples collected in June 2016 showed virus-like symptoms (yellow stripe, mosaic, and dwarfism). Results of reverse transcription polymerase chain reaction (RT-PCR) and sequence comparisons indicated the presence of OYDV and/or LYSV as well as shallot latent virus (SLV). Three of the 66 samples had double infection of SLV and LYSV, and 24 had a mixed infection of all three viruses. This is thought to be the first report of OYDV, LYSV, and SLV on garlic in Tunisia.