Abstract
Abscisic acid (ABA) plays a crucial role in seed maturation as well as acquisition and maintenance of dormancy. Exogenously applied ABA causes delay or inhibition of Arabidopsis seed germination. Little information has been reported for the effects of ABA on gene expression during the inhibition, although many genes are known to be ABA-inducible upon various stresses. As a step toward understanding the mechanism of seed dormancy, we analyzed gene expression in seeds imbibed with or without 3 μM ABA using DNA microarray (Affymetrix GeneChip) and quantitative RT-PCR. Difference in expression profiles at 24-h imbibition either with or without ABA was rather small. Approximately 500 genes showed over 2-fold difference with a relatively low expression level. The effects of (-)-(R)-ABA, an analogue for natural ABA, was also examined. The results suggest that (-)-(R)-ABA activates ABA-inducible genes in similar mechanisms to natural ABA.
