Overexpression of the CBF2 transcriptional Activator Enhances Oxidative Stress Tolerance in Arabidopsis Plants

The C-repeat/dehydration-responsive-element binding factor genes (CBF1-3) are transcriptional activators
involved in governing plant responses to low temperatures; their overexpression enhances plant frost tolerance.
We found that overexpression of CBF2 in Arabidopsis enhanced oxidative stress tolerance as compared with
wild-type plants, an effect that was manifested in: increased seed germination rates on Petri dishes containing
H2O2; delayed leaf senescence following incubation with H2O2; and delayed wilting and senescence after
spraying whole plants with paraquat, a generator of superoxide radicals. Transcript profiling analysis using the
Affymetrix ATH1 genome array revealed that overexpression of CBF2 did not affect expression of reactive
oxygen-scavenging genes but rather, remarkably enhanced expression of oxidative-stress-responsive
transcription factor genes. Overall, the present findings suggest that overexpression of CBF2 in Arabidopsis
enhances oxidative stress tolerance, most likely via activation of a network interaction among stress-related
transcription-factor genes.