Vanilla mosaic virus isolates from French Polynesia and the Cook Islands are Dasheen mosaic virus strains that exclusively infect vanilla

Summary. Sequence was determined for the coat protein (CP) gene and 3′ non-translated region (3′NTR) of two vanilla mosaic virus (VanMV) isolates from Vanilla tahitensis, respectively from the Cook Islands (VanMV-CI) and French Polynesia (VanMV-FP). Both viruses displayed distinctive features in the N-terminal region of their CPs; for VanMV-CI, a 16-amino-acid deletion including the aphid transmission-related DAG motif, and for VanMV-FP, a stretch of GTN repeats that putatively belongs to the class of natively unfolded proteins. VanMV-FP CP also has a novel DVG motif in place of the DAG motif, and an uncommon Q//V protease cleavage site. The sequences were compared to a range of Dasheen mosaic virus (DsMV) strains and to potyviruses infecting orchids. Identity was low to DsMV strains across the entire CP coding region and across the 3′NTR, but high across the CP core and the CI-6K2-NIa region. In accordance with current ICTV criteria for species demarcation within the family Potyviridae, VanMV-CI and VanMV-FP are strains of DsMV that exclusively infect vanilla.