A recombinase polymerase amplification-lateral flow dipstick assay for rapid detection of the quarantine citrus pathogen in China, .

, the causal agent of brown rot of citrus fruit, is an important worldwide pathogen and a quarantine pest in China. Current diagnosis of the disease relies on disease symptoms, pathogen isolation and identification by DNA sequencing. However, symptoms caused by can be confused with those by other and fungal species. Moreover, pathogen isolation, PCR amplification and sequencing are time-consuming. In this study, a rapid assay including 20-min recombinase polymerase amplification targeting the gene and 5-min visualization using lateral flow dipsticks was developed for detecting . This assay was able to detect 0.2 ng of genomic DNA in a 50-µL reaction system. It was specific to without detection of other tested species including , , and , four other important citrus pathogens. Using this assay, was also detected from artificially inoculated orange fruits. Results in this study indicated that this assay has the potential application to detect at diagnostic laboratories and plant quarantine departments of customs, especially under time- and resource-limited conditions.