Radioimmunoassay of the phytotoxic compound zinniol

The phytotoxic compound zinniol, produced by phytopathogenic fungi such as Alternaria spp. and Phoma macdonaldii was conjugated to bovine serum albumine by the mixed anhydride method. Antiserum against zinniol was obtained by injection at multiple intradermal sites of rabbits. Sensitivity of the R.I.A. was 0.14 ng/tube, the within and between-assay coefficient of variation were less than 10 and 14% respectively. Negligible binding occurred when analogs of zinniol were tested for cross reactivity. The excellent accuracy of this R.I.A., applied to ethanolic extracts of plants, might allow to determine the production of toxin by the parasite during the infection process.