Potato deforming mosaic disease is caused by Tomato yellow vein streak begomovirus
In Brazil, a disease called potato deforming mosaic was first reported in the 1980s, in Rio Grande do Sul. Affected potato plants showed leaf distortion and mosaic with yellow blotches, and a virus was suspected to be the causal agent. Until recently the disease remained of little economic importance. In 1997, a new disease was observed on tomato crops near Campinas State of São Paulo (EPPO RS 97/094). Young tomato plants showed yellow streaking of veins on the apical shoots and Bemisia tabaci was able to transmit the pathogen. Research showed that a new virus called Tomato yellow vein streak virus (formerly on the EPPO Alert List) was associated with the disease. Recent studies have now demonstrated that both potato mosaic and tomato yellow vein streak diseases are caused by the same virus: Tomato yellow vein streak begomovirus (ToYVSV). It is noted that this virus is currently the major begomovirus affecting tomatoes and potatoes in the state of São Paulo.
Note: a disease of unknown etiology, also called potato deforming mosaic, was described in Argentina (Delhey et al., 1981), but it is not known whether ToYVSV is involved or not, and what is its current economic impact.
Sources
Ribeiro SG, Inoue-Nagata AK, Daniels J, de Ávila AC (2005) Potato deforming mosaic disease is caused by an isolate of Tomato yellow vein streak virus. New Disease Report Volume 12 August 2005-January 2006. http://www.bspp.org.uk/ndr/jan2006/2005-70.asp
Delhey R, Kiehr-Delhey M, Heinze K, Calderoni AV (1981) Symptoms and transmission of potato deforming mosaic of Argentina. Potato Research 24(2), 123-133 (abstract).