GEL PENETRATE-BLOTTED IMMUNOBINDING ASSAY, A NOVEL METHOD FOR SEROLOGICAL DETECTION OF FUSARIUM SPP. IN SOIL

A new serological method for the detection of Fusarium spp. in soil wa s established. On a sheet of nitrocellulose membrane, about 1 mm thick layer of agar gel was overlaid, and soil sample suspension was spread over the gel. After 10 to 20 hr of incubation, fungi in the sample gr ew through the gel-layer and reached the membrane leaving the soil par ticles on the gel surface. The membrane blotted with the fungi was rec overed, and was treated with a monoclonal antibody API9-2 against Fusa rium spp., secondary antibody labeled with alkaline phosphatase, and f inally the substrate solution. The samples of Fusarium-infested soil s uccessfully showed positive reaction an the membrane by this immunobin ding assay (IBA). We named the method as gel penetrate-blotted immunob inding assay (GP-IBA). As the series of assay procedures can be comple ted within 24 hr and the detection limit is estimated to be about 10(3 ) conidia/g soil, this method is considered to be suitable for detecti on of Fusarium spp. in soil.