A MONOCLONAL-ANTIBODY AGAINST THE PLANT-GROWTH REGULATOR, ABSCISIC-ACID

Monoclonal antibodies were prepared against the plant growth regulator abscisic acid (ABA) conjugated to keyhole limpet hemocyanin through C -4. One of these antibodies was characterized for use in a competition fluorescence enzyme-linked immunosorbent assay (F-ELISA). The antibod y detected femtomole quantities of ABA when used in the F-ELISA and sh owed minimal cross-reactivity with ABA metabolites and structural anal ogs. Dilution analysis suggested that the F-ELISA could be used to det ermine the ABA content of methanolic extracts of crude samples of whea t seeds without further purification. The F-ELISA was used to determin e the effect of seed priming on ABA levels in wheat seeds. The antibod y also was used in a modified noncompetitive indirect ELISA to measure ABA content of wheat caryopses. The noncompetitive ELISA was more sen sitive than the F-ELISA, although the F-ELISA had a broader measuring range. When our anti-ABA antibody and a commercially available anti-AB A antibody were compared by indirect ELISA, there were no significant differences between the ABA estimates.