Open AccessThe 7[prime]-Methyl Group of Abscisic Acid Is Critical for Biological Activity in Wheat Embryo Germination
Author(s) -
M. K. WalkerSimmons,
Patricia A. Rose,
A. Shaw,
Suzanne R. Abrams
Publication year - 1994
Publication title -
plant physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.554
H-Index - 312
eISSN - 1532-2548
pISSN - 0032-0889
DOI - 10.1104/pp.106.4.1279
Subject(s) - abscisic acid , germination , prime (order theory) , enantiomer , chemistry , stereochemistry , methyl group , embryo , biology , biochemistry , botany , group (periodic table) , organic chemistry , mathematics , combinatorics , gene , microbiology and biotechnology
Wheat (Triticum aestivum L.) embryo germination is inhibited by natural (S)-(+)-abscisic acid (ABA). In this report we have determined critical structural features of the ABA molecule, particularly the methyl and ketone groups of the ABA ring, required for inhibitory activity. To examine the ring residues a series of new optically active ABA analogs have been synthesized in which the 4[prime]-keto, 7[prime]-, 8[prime]-, or 8[prime]- and 9[prime]-carbons have been replaced with hydrogen atoms. Each of the analogs was tested over a range of concentrations as a germination inhibitor. Enantiomers of the analogs altered at the 4[prime]-keto or 8[prime]- and 9[prime]-methyl groups were active, but less so than ABA. Both enantiomers of 7[prime]-demethylABA were inactive as germination inhibitors. The results show that the 7[prime]-methyl group is absolutely required for activity, but that the other residues are less critical for hormone recognition.