Evidence that an unnamed isometric virus associated with potato rugose disease in Peru Is a new species of genus Torradovirus

Authors: ALVAREZ-QUINTO, ROBERT - Oregon State University; AMAO, MELODIE - International Potato Center; MULLER, GIOVANNA - International Potato Center; FUENTES, SEGUNDO - International Potato Center; Grinstead, Sam; Fuentes-Bueno, Irazema; ROENHORST, ANNELIEN - Netherlands Food And Consumer Production Safety Authority(NVWA); WESTENBERG, MARCEL - Netherlands Food And Consumer Production Safety Authority(NVWA); BOTERMANS, MARLEEN - Netherlands Food And Consumer Production Safety Authority(NVWA); KREUZE, JAN - International Potato Center; Mollov, Dimitre

Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/11/2023
Publication Date: 10/28/2023
Citation: Alvarez-Quinto, R., Amao, M., Muller, G., Fuentes, S., Grinstead, S.C., Fuentes-Bueno, I., Roenhorst, A., Westenberg, M., Botermans, M., Kreuze, J., Mollov, D.S. 2023. Evidence that an unnamed isometric virus associated with potato rugose disease in Peru Is a new species of genus Torradoviru. Phytopathology. 113(9):1943-7684. https://doi.org/10.1094/PHYTO-11-22-0449-V.
DOI: https://doi.org/10.1094/PHYTO-11-22-0449-V

Interpretive Summary: Potato is a staple food and ranks third among the most important crops for human consumption. Potato production is hindered by pest and diseases, many of which are caused by viruses. In this research we described a previously identified but poorly characterized virus documented to occur in the Andes. Potato tubers were intercepted by Customs and Border Protection in Miami, FL, and later by the customs authorities in the Netherlands. In both cases these potatoes were infected with the same virus from the Andes. We determined the virus genomic sequence and through surveys in Peru identified multiple isolates. Additionally, the South American potato psyllid which is not present in the U.S. was considered to vector this virus. Identifying the vector transmitting the virus can be used in devising better management strategies. All combined data allows us to develop detection assays that can be used to monitor potato material introduced to the U.S. which will allow us to keep this pathogen out of the potato production areas in North America.

Technical Abstract: A previously uncharacterized torradovirus species infecting potatoes was detected by high-throughput sequencing from field samples in Peru, and custom intercepts in the USA and the Netherlands in potato tubers originated from South America. The new potato torradovirus showed high similarity to an isolate of an unidentified isometric virus, coded SB26/29, characterized over 25 years ago causing a disease named potato rugose stunting in southern Peru and is tentatively named potato rugose stunting virus (PotRSV). PotRSV isolates sequenced in this study contain two polyadenylated RNA segments. RNA1 ranges between 7,086-7,089 nt and RNA2 from 5,228 to 5230 nt. RNA-1 encodes a polyprotein containing the replication block (Helicase-Protease-Polymerase), whereas RNA2 encodes a polyprotein including a movement protein and three capsid proteins domains. PotRSV isolates sequenced in this study share amino acid identity values >86% in the protease-polymerase region and >82% for the combined coat proteins. The closest torradovirus species to PotRSV is squash chlorotic leaf spot virus sharing 41% of identity at the amino acid level. Emergence of potato rugose stunting disease was associated with high populations of the South American potato psyllid (Russelliana solanicola Tuthill) and transmission studies indicated that it is a vector of PotRSV.