First report of Potato yellowing virus in Ecuador
In the early 1990s, Potato yellowing virus (Ilarvirus, PYV – EPPO A1 List) was reported from potato (Solanum tuberosum) fields showing leaf chlorosis in Peru, and from symptomless wild potatoes (S. fernandezianum) in Chile (see EPPO RS 1993/151 and 2006/273). More recently, the presence of PYV has been detected in S. phureja (potato) collected from Ecuador where this crop constitutes an important source of income in rural communities. In addition, forty accessions of S. phureja collected from Ecuador in 1986 and maintained in vitro at the International Potato Center (CIP) germplasm bank were tested for PYV (DAS-ELISA). Results showed that PYV was present in 6 S. phureja accessions (15% of the material) which had been collected from different provinces (Azuay, Cañar, Loja), thus suggesting that the virus might be more widely spread than originally thought.
Until these studies, PYV was considered as an alfamo-like virus (family Bromoviridae) but as no sequence information was available, its taxonomic position within the Bromoviridae (which includes 5 genera: Alfamovirus, Bromovirus, Cucumovirus, Ilarvirus and Oleavirus) was uncertain. While studying isolates of PYV from Ecuador, phylogenetic analysis could be performed, and PYV sequences could be grouped with those of viruses of the genus Ilarvirus (Fragaria chiloensis latent virus being the closest relative). The authors concluded that PYV should be considered as member of the genus Ilarvirus.
Sources
Silvestre R, Untiveros M, Cuellar WJ (2011) First report of Potato yellowing virus (genus Ilarvirus) in Solanum phureja from Ecuador. Plant Disease 94(3), p 335.