Determination of the complete genome of European mountain ash ringspot-associated emaravirus from Sorbus intermedia reveals two additional genome segments. EMARaV in Sorbus intermedia

We report the complete genome sequence comprising 6 single stranded RNAs of negative orientation of a European mountain ash ringspot-associated virus (EMARaV) isolate identified in a diseased Sorbus intermedia (Swedish whitebeam) tree exhibiting prominent chlorotic ringspots, mottle and line pattern on leaves. Since the first observation of EMARaV-like symptoms and detection of the virus in whitebeam in 2012, the tree displayed leaf symptoms every year at least in one third of its canopy, developed dieback symptoms and showed signs of decline. Two previously unrecorded genome segments of the virus were identified, each encoding in negative orientation a single protein. RNA5 is 1629 nucleotides long and encodes the putative movement protein (MP) of EMARaV with a molecular mass of 42.4 kDa. RNA6 (1362 nucleotides) encodes a small protein (26.8 kDA) exhibiting some homology with the P4 protein encoded by EMARaV RNA4. However, its biological function remains to be elucidated. Both novel genome segments are systematically present in EMARaV-infected Sorbus spp. and no additional genome segments could be identified by two independent methods. It is concluded that the 6 RNAs represent the complete genome of EMARaV.