Abstract
A cis-acting promoter element DRE/CRT plays an important role in regulating gene expression in response to drought, salt and cold stress. We have reported that Arabidopsis transcription factors DREBs bind to DRE and control expression of many stress-responsive genes. Overexpression of DREB1A in transgenic Arabidopsis activated the expression of the target stress-responsive genes and resulted in improved stress tolerance. In rice, we isolated cDNAs for DREB homologues, OsDREBs.
We generated transgenic rice overexpressing the DREB or OsDREB genes. These transgenic rice plants revealed drought stress tolerance and contents of free proline in the transgenics are higher than those of control plants. We carried out microarray analysis using the transgenics and identified several target stress-inducible genes of DREB in rice. The promoter regions of these genes contain DRE-related motifs. These results indicate that there is a similar DRE/DREB regulon in the stress-responsible signal transduction in rice.
