Abstract
DREB2A is a transcription factor that functions in drought and high-salinity responsive gene expression. DREB2A has a negative regulatory domain in the central region, and deletion of this region makes DREB2A a constitutive active form (DREB2A CA). We generated transgenic Arabidopsis plants overexpressing DREB2A CA. The microarray analysis of the transgenic plants revealed that, in addition to many water-stress inducible genes, heat-shock (HS) related genes were expressed in the transgenic plants even under non-stressed condition. Moreover, we found that transient induction of the DREB2A occurs rapidly by HS stress, and that the sGFP-DREB2A protein accumulates in nuclei of HS-stressed cells. DREB2A up-regulated genes were down-regulated in DREB2A knockout mutants under stress conditions. Thermotolerance was significantly increased in plants overexpressing DREB2A CA and decreased in DREB2A knockout plants. These results suggest that DREB2A may be involved in not only drought and high-salinity response but also heat-shock response.
