Potato rugose stunting virus, a newly characterized potato virus
In the 1990s, a previously uncharacterized disease of viral aetiology was observed in cultivated potatoes (Solanum tuberosum) in Southern Peru. It was named potato rugose stunting disease (PRSD) and was reported to cause severe symptoms in infected potato plants, including mosaic and deformation of the leaves and stunting (EPPO RS 2006/237).
Studies showed that the disease was caused by an unknown isometric virus, which was provisionally coded SB26/29. This virus had been intercepted on potato in the Netherlands and in the USA. SB26/29 was categorized as a potential quarantine pest for the European Union by EFSA but has not yet been added to the EU quarantine lists.
Recent research further characterized this virus and showed that it belonged to the genus Torradovirus and is a new species tentatively named potato rugose stunting virus (PotRSV).
Surveys in Peru detected PotRSV in the regions of Cusco, Huánuco, Ica, Junín, Lima, and Puno with a low incidence (2.3 to 5.5%). PotRSV was often found in mixed infections but when found alone, leaf symptoms ranged from mild mosaic to stunting and rugosity. Although it was suggested in the past that this virus could be transmitted by the psyllid Russelliana solanicola, vector transmission experiments performed by the authors using two insect species, Myzus persicae and R. solanicola were not successful.
Host range studies with artificial inoculation showed that tomato (Solanum lycopersicum) and pepper (Capsicum annuum) could be asymptomatic hosts.
Sources
Alvarez Quinto RA, Amao M, Muller G, Fuentes S, Grinstead S, Fuentes-Bueno I, Roenhorst A, Westenberg M, Botermans M, Kreuze J, Mollov D (2023) Evidence that an unnamed isometric virus associated with potato rugose disease in Peru is a new species of torradovirus. Phytopathology 113(9), 1716-1728. https://doi.org/10.1094/PHYTO-11-22-0449-V
EFSA Panel on Plant Health (2020) Pest categorisation of non‐EU viruses and viroids of potato. EFSA Journal 18(1), e05853. https://doi.org/10.2903/j.efsa.2020.5853