The Commercial Validation of Three Tomato Brown Rugose Fruit Virus Assays

Tomato brown rugose fruit virus (ToBRFV) was first described infecting tomatoes in 2015 after breaking tobamovirus resistance in production cultivars. As an emerging pathogen, ToBRFV commercial assays were developed and subsequently validated. Agdia commercialized three ToBRFV assays: ELISA, ImmunoStrip, and AmplifyRP XRT. The ToBRFV ELISA is a serological method utilizing monoclonal antibodies designed for use as a high-throughput laboratory tool. The ToBRFV ImmunoStrip is a serological lateral flow device utilizing monoclonal antibodies designed for use as a field-screening tool. The ToBRFV XRT is a molecular method utilizing recombinase polymerase amplification designed to be a hybrid field-screening/laboratory tool with PCR-like sensitivity. The performance criteria and validation requirements for the three assays were chosen and evaluated based on each product's fitness for purpose. The ELISA and ImmunoStrip both have an analytical sensitivity of 64 to 320 pg/ml and an analytical specificity inclusive of all tested ToBRFV isolates with cross-reactions to tobacco mosaic virus, tomato mosaic virus, and tomato mottle mosaic virus. The XRT has an analytical sensitivity of 15 fg/mu l and an analytical specificity inclusive of all tested ToBRFV isolates with no cross-reactions. All three assays have both a diagnostic sensitivity and specificity of 100%. Reliable diagnostic and analytical data are necessary for commercial assays to be both accepted by and useful to diagnosticians, researchers, and breeders. Without adequate validation, false results and/or false reporting can occur. In the absence of formal validation requirements in the global plant pathogen diagnostic community, Agdia commercialized ToBRFV ELISA, ImmunoStrip, and AmplifyRP XRT assays and evaluated them based on publicly available and internal performance criteria.Copyright (c) 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.