Comparative analysis of abscisic acid-regulated transcriptomes in Arabidopsis

Transcription regulation by the phytohormone abscisic acid (ABA) plays a key role in responses to various stresses and has been extensively studied in Arabidopsis thaliana using different expression analysis techniques. Previous studies on comparative analysis of expression regulation by ABA and ABA-related stresses demonstrated marked differences in the targets of ABA. However, as few expression experiments were available during these studies, they encompass only a subset of ABA-regulated genes. The aim of the present work was to compare gene expression regulated by ABA administration in a wider range of expression experiments. Despite diversity in the actual set of genes regulated by ABA, all ABA-regulated transcriptomes shared some basic features, such as a common induced gene set, common functional targets and involvement of common regulatory mechanisms. Moreover, the cis-regulatory architecture of genes belonging to this set is expected to be of interest because of their sensitivity to ABA and apparent independence from other experimental variables. Comparative analysis of cis-regulatory element (CRE) enrichment also identified a novel CRE that is strongly associated with ABA signalling-mediated transcription repression.