Combating Rose Rosette Disease: Development of Rapid, Efficient, User-friendly Virus Diagnostic Tools and Studying Virus–Vector Interactions

Over the past few decades, Rose Rosette Disease (RRD) has spread from its source in the Rockies, through the Mid-West to the East coast. It now threatens to decimate the US rose industry. Garden roses, which form the cornerstone of the multi-billion dollar landscape industry, annually generate wholesale US domestic bare root and container production valued at ~ $400 million. There is an urgent need to control RRD.  It is caused by a novel plant virus, the Rose rosette virus (RRV), which is transmitted by wind-blown eriophyid mites (Phyllocoptes fructiphilus). Unlike other rose diseases it can kill a rose within two to three years of infection.  A newly-funded USDA, NIFA, Specialty Crops Research Initiative Program Project involves 17 scientists in 6 states working on a range of approaches to learn more about this disease and determine how best to manage it. The long term goal of this project is to develop roses resistant to this virus and/or mite vector. Key to this effort will be the development of efficient diagnostic tools to enable rapid, easy-to-use and accurate detection of the virus. RRV-specific primers and probes (for nucleic acid-based assays) and monoclonal and/or single-chain antibodies (for serological-based tests) will be designed and developed.   Lateral flow devices (for both antibody and nucleotide based detection), for in-field detection systems, as well as ELISA, RT-LAMP (Reverse transcription-Loop mediated isothermal amplification of DNA) and self-quenched primer (SqP) technologies (for laboratory detection systems) will be developed. The most consistent assay will be tested and validated by several diagnostic labs and then moved via outreach to other plant diagnostic labs.  Interactions between the mite vector and rose hosts will also be studied.  Rose genotypes that are either resistant or susceptible to mite feeding, reproduction, or RRV transmission will be examined by low temperature scanning electron microscopy. We hope to identify differences in leaf surface properties that can be utilized for screening breeding lines. The breeding aspect of the project includes the field evaluation of 400 roses for RRD resistance. In the long term, this project hopes to identify additional sources of resistance and develop hybridization and genetic tools to move resistance into commercial cultivars.