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Techniques

An Indirect Enzyme-Linked Immunosorbent Assay for Measurement of Abscisic Acid in Soybean Inoculated with Phytophthora megasperma f. sp. glycinea. D. M. Cahill, Agriculture Canada, Research Centre, 1400 Western Road, London, Ontario, Canada, N6G 2V4; E. W. B. Ward, Agriculture Canada, Research Centre, 1400 Western Road, London, Ontario, Canada, N6G 2V4. Phytopathology 79:1238-1242. Accepted for publication 7 June 1989. Copyright 1989 Department of Agriculture, Government of Canada. DOI: 10.1094/Phyto-79-1238.

An indirect enzyme-linked immunosorbent assay (ELISA) was developed to measure the concentration of abscisic acid (ABA) in soybean hypocotyl tissues after inoculation with Phytophthora megasperma f. sp. glycinea. The assay, which uses monoclonal antibodies, has a measuring range of 5–250 pg of ABA. Validation of the assay with high-performance liquid chromatography showed that the assay is a sensitive and reliable method for the determination of ABA in crude tissue extracts. In an incompatible interaction the concentration of ABA in lesions was reduced to 32% of uninoculated control levels by 6 hr after inoculation.