Habituation in in vitro soybean cultures

The habituation of soybean (Glycine max) callus can be induced rapidly, by exposing the tissue to small amounts (10⁻⁹molar) of compounds including 2.4-dinitrophenol and phenoxyisobutyric acid for brief periods of time. Such compounds reportedly exhibit antiauxin activity. Various soybean callus phenotypes have been isolated which continue to exhibit hormone habituation 14 months following the initiation of the experiment. Protein changes in habituated tissue under selected hormonal regimes were detected indicating changes at the level of gene expression. Habituated tissue exhibits hormonal autonomy in a manner similar to crown gall tissue, suggesting that such studies may help elucidate the mechanism of induction of crown gall disease and genetic transformation by Agrobacterium.