Comparative transcriptome of diurnally oscillating genes and hormone-responsive genes in Arabidopsis thaliana: insight into circadian clock-controlled daily responses to common ambient stresses in plants.

By adopting two distinct types of comprehensive transcriptome data sets, which are available to the public, we asked the critical question as to whether or not there is any significant correlation between diurnally oscillating genes during the light/dark daily cycle and hormone-responsive genes. The hormones studied here were ABA, ethylene, brassinosteroid, cytokinin, gibberellin, auxin and jasmonate. It was revealed that the expression of a significantly large number of ABA-responsive and/or methyl jasmonate (MJ)-responsive genes oscillate diurnally and robustly during the light/dark cycle. The results of this study implied that some aspects of plant stress responses, basically mediated by ABA and/or MJ, might be regulated daily though the circadian clock function at the level of transcription in order to prepare properly for action against common ambient stresses by anticipating the diurnal day/night cycle.