Analysis of transgenic Arabidopsis plants overexpressing a constitutive active form of DREB2A, a transcription factor that plays a important roll in responses to dehydration- and salt-stress.

Abstract

DREB2A is a transcriptional factor that functions in drought- and high-salinity-responsive gene expression. This protein specifically binds to DRE/CRT in the promoter region of stress-inducible genes. It seems that a post-translational modification is necessary for its activation. We carried out domain analysis of DREB2A and found that a negative regulatory domain exists in the central region of DREB2A and deletion of this region makes DREB2A constitutive active form (DREB2A CA). We generated transgenic Arabidopsis plants overexpressing 35S:DREB2A CA. The transgenic plants showed growth retardation and improved drought stress tolerance. The microarray analysis revealed that many water-stress inducible genes were expressed in the transgenic plants even under non-stress condition. We analyzed the DRE/CRT core sequence in the promoter regions of the DREB2A target genes. We also generated transgenic plants overexpressing DREB2A CA driven by the stress-inducible promoter and analyzed their phenotypes and stress tolerance.