A rapid and simplified detection of Agroathelia rolfsii (syn. Sclerotium rolfsii) by LAMP assay in fields

Abstract Agroathelia rolfsii (syn. Sclerotium rolfsii) causes southern blight and root rot in various agricultural crops. In soybean, this pathogen attacks host roots and stems near the ground, and then forms abundant sclerotia which have an ability to overwinter and survive in soil for a long time. In the Kyoto Prefecture, Japan, damping-off disease in black soybean seedlings is caused by A. rolfsii and is a threat to sustainable production. To circumvent expansion of inoculum resource, A. rolfsii-infected soybean seedlings must be identified as soon as possible. In this study, we developed a loop-mediated isothermal amplification (LAMP) assay for A. rolfsii. A positive reaction of the LAMP assay was detected in A. rolfsii, but not Calonectria ilicicola and Phytophthora sojae. The LAMP assay is completed within 1 h. The detection sensitivity of the LAMP assay was 1000 times higher than that of conventional PCR. Moreover, the LAMP assay could detect A. rolfsii-infected soybean seedlings in fields, achieving practical diagnosis technique. Taken together, our technique allows for rapid and simplified diagnosis and contributes to disease management.