Evidence that an Unnamed Isometric Virus Associated with Potato Rugose Disease in Peru Is a New Species of Genus Torradovirus

A previously uncharacterized torradovirus species infecting potatoes was detected by high-throughput sequencing from field samples from Peru and in customs intercepts in potato tubers that originated from South America in the United States of America and the Netherlands. This new potato torradovirus showed high nucleotide sequence identity to an unidentified isometric virus (SB26/29), which was associated with a disease named potato rugose stunting in southern Peru characterized over two decades ago. Thus, this virus is tentatively named potato rugose stunting virus (PotRSV). The genome of PotRSV isolates sequenced in this study were composed of two polyadenylated RNA segments. RNA1 ranges from 7,086 to 7,089 nt and RNA2 from 5,228 to 5,230 nt. RNA1 encodes a polyprotein containing the replication block (helicase-protease-polymerase), whereas RNA2 encodes a polyprotein cleaved into a movement protein and the three capsid proteins (CPs). Pairwise comparison among PotRSV isolates revealed amino acid identity values greater than 86% in the protease-polymerase (Pro-Pol) region and greater than 82% for the combined CPs. The closest torradovirus species, squash chlorotic leaf spot virus, shares amino acid identities of similar to 58 and similar to 41% in the Pro-Pol and the combined CPs, respectively.Copyright (c) 2023 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.

Automated summary

A new torradovirus species called potato rugose stunting virus (PotRSV) was detected in potatoes from Peru, the United States, and the Netherlands. The virus has high sequence identity to an unknown isometric virus associated with potato rugose stunting disease in Peru. The genome of PotRSV consists of two RNA segments, with RNA1 encoding a replication-related polyprotein and RNA2 encoding a movement protein and capsid proteins.