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Techniques

Novel Enzyme Immunoassays for Specific Detection of Fusarium oxysporum f. sp. cucumerinum and for General Detection of Various Fusarium Species. Tsunehiro Kitagawa, Professor, Department of Microbiological Chemistry, Faculty of Pharmaceutical Sciences, Nagasaki University, Nagasaki, 852 Japan; Yuichiro Sakamoto(2), Katsuhiko Furumi(3), and Hirosuke Ogura(4). (2)(3)Postgraduate students, Department of Microbiological Chemistry, Faculty of Pharmaceutical Sciences, Nagasaki University, Nagasaki, 852 Japan; (4)Professor, Department of Plant Pathology, Faculty of Agriculture, Kochi University, Nankoku, Kochi 783, Japan. Phytopathology 79:162-165. Accepted for publication 11 August 1988. Copyright 1989 The American Phytopathological Society. DOI: 10.1094/Phyto-79-162.

Competitive types of two novel enzyme-linked immunosorbent assays (ELISA) for Fusarium species were developed. Antiserum against a strain (F504) of F. oxysporum was elicited in rabbits, and a highly specific, sensitive, and accurate ELISA for the homologous strain was developed by using the antiserum with Beta-d-galactosidase-labeled anti-rabbit IgG as the secondary antibody and cell fragments of the strain attached to Amino-Dylark balls as the solid-phase antigen. All other microorganisms tested, including nine other strains of Fusarium, showed little cross-reactivity. When cell fragments of F. oxysporum F501 attached to the balls were used as a solid-phase antigen in a heterologous competitive ELISA, the modified system was a general assay for 10 strains of four Fusarium species with a high sensitivity. The specificity of the heterologous competitive ELISA was shown to be limited to Fusarium species. The reason for developing the improved ELISA is also presented.