Rapid detection of Fusarium oxysporum f. sp lactucae on soil, lettuce seeds and plants using loop-mediated isothermal amplification

Fusarium oxysporum f. sp. lactucae (FOL) is a soil- and seedborne pathogen and the causal agent of fusarium wilt on lettuce. Four races have been identified within FOL, with different worldwide distribution. Several molecular techniques have been used to detect and identify this pathogen; however, not all of them have the optimal characteristics in terms of sensitivity to perform FOL detection in plant and seed material. A loop-mediated isothermal amplification (LAMP) assay was developed based on the sequence-characterized amplified region (SCAR) obtained in a previous rapid amplification of polymorphic DNA (RAPD) study. The LAMP assay has been validated according to the EPPO standard PM7/98. The LAMP assay was tested with lettuce seeds, soil and plant material, and can be used successfully to amplify DNA from each of these matrices. In seed lots artificially inoculated with FOL, the detection limit of the LAMP test was 0.004% infected seed.