The role of TaABF1 in helping Plants respond to Hormones
The plant hormones abscisic acid (ABA) and gibberellin (GA) have opposing effects on germination and other developmental processes in imbibing cereal grains. Underlying these developmental processes are changes in gene expression that are brought about by GA and ABA. To investigate how hormones regulate gene expression in wheat plants, we have focused on the transcription factor TaABF1. We found that TaABF1 plays a role in both ABA-mediated suppression of genes induced by GA and in ABA-induced expression of other genes. TaABF1 apparently carries out these two roles via different mechanisms as suppression of GA-induced genes is much more sensitive to low levels of TaABF1 than is stimulation of ABA-induced gene expression. Inhibition of ABA perception by cells prevented the ability of TaABF1 to stimulate ABA-induced gene expression, suggesting that TaABF1 protein must be modified in response to ABA before it is able to function in gene regulation.