Rapid detection of Impatiens necrotic spot virus from thrips vectors using reverse transcription-recombinase polymerase amplification

Authors: Zhang, Shulu; Hladky, Laura; Hasegawa, Daniel

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/13/2024
Publication Date: 9/20/2024
Citation: Zhang, S., Hladky, L.L., Hasegawa, D.K. 2024. Rapid detection of Impatiens necrotic spot virus from thrips vectors using reverse transcription-recombinase polymerase amplification. Scientific Reports. 14. Article 21946. https://doi.org/10.1038/s41598-024-73078-4.
DOI: https://doi.org/10.1038/s41598-024-73078-4

Interpretive Summary: Lettuce is a high-value leafy green vegetable that is grown in California. In recent years, a disease caused by Impatiens necrotic spot virus (INSV) has resulted in severe economic losses for the industry. INSV is transmitted by thrips, a small and ubiquitous insect that is endemic to the region. Both thrips and INSV have a large host range of plant species that support their persistence in the natural environment, creating additional management challenges. Here, we developed a new molecular diagnostic tool to rapidly detect INSV from thrips, as well as lettuce plants. The tool provides advantages such that it is cheaper, faster, and equally accurate at detecting INSV compared to traditional diagnostic methods. The new tool enhances our ability to identify emerging virus-infected thrips populations to predict where virus outbreaks may occur in lettuce production.

Technical Abstract: The plant virus, Impatiens necrotic spot virus (INSV), is an economically important pathogen of vegetables, fruits, and ornamental crops. INSV is vectored by the western flower thrips, Frankliniella occidentalis, a small insect pest that is globally distributed. In recent years, INSV outbreaks have reached epidemic levels in the Salinas Valley of California – an agriculturally rich region where most of the lettuce (Lactuca sativa) is produced in the United States. Due to the obligate nature in which virus transmission occurs, new tools that could rapidly detect INSV from thrips vectors would enhance our ability to predict where virus outbreaks may occur. Here, we report on the development of a reverse transcription-recombinase polymerase amplification (RT-RPA) assay that can detect INSV from individual thrips. The assay uses crude extraction methods, is performed at a single temperature of 42 °C, can be completed in 25 minutes, and provides sensitivity levels that are comparable to other available detection methods. When the assay was used on field populations of thrips, INSV was successfully identified and quantified from individual larvae and adults. The work provides a new cost-effective surveillance tool that can rapidly detect INSV from its insect vector and from plants.