Barley yellow dwarf virus in barley crops in Tunisia: prevalence and molecular characterization

A field survey was conducted in Tunisia in the North-Eastern regions (Bizerte, CapBon and Zaghouan), the North-Western region (Kef) and the Central-Eastern region (Kairouan) during the 2011/2012 growing season, in order to determine the incidence and the geographic distribution of Barley yellow dwarf virus (BYDVs) in barley fields. Tissue blot immunoassays (TBIA) showed that BYDV was most common in Zaghouan (incidence 14%), Cap Bon (14%) and Bizerte (35%), in randomly collected samples from these three locations.Among the different BYDVs identified, BYDV-PAV (64%) was the most common followed by BYDV-MAV (16%) and CYDV-RPV (3%). The coat protein gene sequences of six isolates collected from different regions shared >98% pairwise similarity. In comparisons with other BYDV sequences from around the world, the Tunisian sequences snared greatest homology with isolates 109 and ASL1 from the United States of America and Germany (≈97%), and