Abstract
We have reported that Arabidopsis transcription factors DREB1s control expression of many stress-responsive genes. In rice, we isolated cDNAs for DREB1-type proteins, OsDREB1s.
In this study we analyzed function of OsDREB1F, which has high homology to Arabidopsis DREB1E/F, using transgenic Arabidopsis and rice plants. Expression of OsDREB1F was induced strongly but transiently by touch, though OsDREB1A was induced strongly by cold stress. In transgenic Arabidopsis overexpressing OsDREB1F, the same downstream genes were up-regulated as those in transgenic Arabidopsis overexpressing DREB1E/F.
Using transgenic rice plants overexpressing OsDREB1F, we performed microarray analysis and found that many genes were up-regulated as compared with those in wild-type plants. On the other hand, using RNA interference (RNAi) we generated loss-of-function mutants of OsDREB1F, which showed promoted growth as compared with wild-type plants. These results indicate that OsDREB1F plays an important role in growth regulation. Currently we are analyzing downstream genes in the OsDREB1F loss-of-function mutants.
