Abstract
We have reported that Arabidopsis transcription factors DREBs 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 revealed drought, high-salt and cold stress tolerance and contents of various osmoprotectants in the transgenics are higher than those of control plants. We carried out microarray analysis using the transgenics and identified several target genes of DREB in rice. These results indicate that the DREB gene family is quite useful for improvement of tolerance to environmental stresses in rice.
However, these plants overexpressing DREB genes show growth retardation and dwarf phenotype. To minimize the negative effect on plant growth, we generated transgenic rice overexpressing DREB genes driven by a stress-inducible promoter.
