Rapid and simple detection of Phytophthora cactorum in strawberry using a coupled recombinase polymerase amplification-lateral flow strip assay

Phytophthora cactorum is a devastating pathogen that infects a wide range of plants and causes Phytophthora rot disease, which has resulted in great economic losses in crop production. Therefore, the rapid and practicable detection of P. cactorum is important for disease monitoring and forecasting. In this study, we developed a lateral flow recombinase polymerase amplification (LF-RPA) assay for the sensitive visual detection of P. cactorum. Specific primers for P. cactorum were designed based on the ras-related protein gene Ypt1; all 10 P. cactorum isolates yielded positive detection results, whereas no cross-reaction occurred in related oomycete or fungal species. The detection limit for the LF-RPA assay was 100 fg of genomic DNA under optimized conditions. Combined with a simplified alkaline lysis method for plant DNA extraction, the LF-RPA assay successfully detected P. cactorum in naturally diseased strawberry samples without specialized equipment within 40 min. Thus, the LF-RPA assay developed in this study is a rapid, simple, and accurate method for the detection of P. cactorum, with the potential for further application in resource-limited laboratories.

Automated summary

A lateral flow recombinase polymerase amplification (LF-RPA) assay was developed for sensitive visual detection of Phytophthora cactorum, with a detection limit of 100 fg of genomic DNA. The assay successfully detected P. cactorum in naturally diseased strawberry samples within 40 minutes, making it a rapid, simple, and accurate method for detection with potential for application in resource-limited laboratories.