A Loop-Mediated Isothermal Amplification Assay for the Identification of in Strawberry.

Gray mold in strawberry is caused by multiple species of , including , , , and . The species and are widespread in production regions of the eastern United States and Germany, and their distinction is important for disease management strategies. Currently, the only way to differentiate these species in field samples is by PCR, which is time consuming, labor intensive, and costly. In this study, a loop-mediated isothermal amplification (LAMP) technique was developed based on species-specific gene nucleotide sequences. The designed primer set specifically amplified DNA and no other spp. (, , and ) or plant pathogens. The LAMP assay was able to amplify fragments from DNA extracted from infected fruit using a rapid DNA extraction protocol, confirming its ability to detect low amounts of DNA from field-infected fruit. In addition, a blind test was performed to identify in 51 samples collected from strawberry fields in the eastern United States using the LAMP technique. The samples were identified with a reliability of 93.5% (29 of 32), and none of the , , or samples included in the test were amplified in 10 min. Our results show that the LAMP technique is a specific and reliable method for the detection of from infected fruit tissue and can help to control this important disease in the field.