2017 ASHS Annual Conference

Downy mildew caused by Peronospora destructor is one of the most destructive diseases of onion. Early and rapid detection of Peronospora destructor is important for the disease forecasting and management. In this study, we developed a loop-mediated isothermal amplification (LAMP) assay using DNA extracted from leaf blades of diseased onion for visual detection. A set of two primers was designed from the internal transcribed spacer (ITS) region of rDNA of Peronospora destructor. The LAMP reaction was optimal at 64°C for 45 min. When hydroxynaphthol (HNB) was added, samples with Peronospora destructor DNA developed a sky blue color but those negative control or with the DNA of other plant pathogenic fungi did not. Results of LAMP reaction were reconfirmed by gel electrophoresis. This detection limit of the LAMP assay for Peronospora destructor was 7.25fg/㎕ of genomic DNA per reaction, which was 10 times more sensitive than conventional PCR. These results suggest that LAMP assay is suitable for the early and rapid detection of Peronospora destructor in infected onion, and contributes to the effective control of onion downy mildew in the field.

 This study was financially supported by the Korea Institute of Planning and Evaluation for Technology in Food, Agriculture, Forestry and Fisheries, the Advanced Production Technology Development Program, Ministry for Agriculture, Food and Rural Affairs, Republic of Korea.