The biological and structural similarity between lunularic acid and abscisic acid

Abstract

Lunularic acid (LA) inhibited not only the germination and the growth of cress and lettuce at 1 mM but also the gibberellic acid (GA3)-induced α-amylase induction in embryoless barley seeds at 120 μM, which was recognized as a specific activity of abscisicacid (ABA). Moreover LA and ABA equally inhibited the growth of Lunularia cruciata A18 strain callus at 40 and 120 μM. A computational analysis revealed that the stable conformers of LA could be superimposed on the stable ABA conformers. In addition, the antibody raised against theconjugate of C1-ABA-bovine serum albumin (ABA-BSA) reacted with LA-horse-radish peroxidase (LA-HRP) conjugate as well as ABA-HRP conjugate, apparently. These results can explain whyLA has ABA-like activity in higher plants. Moreover the results suggest that LA and ABA bind to the same receptor in higher plants. © 2002 by Japan Society for Bioscience, Biotechnology, and Agrochemistry.