ARABIDOPSIS CBF1 OVEREXPRESSION INDUCES COR GENES AND ENHANCES FREEZING TOLERANCE

Many plants, including Arabidopsis, show increased resistance to freez ing after they have been exposed to low nonfreezing temperatures. This response, termed cold acclimation, is associated with the induction o f COR (cold-regulated) genes mediated by the C-repeat/drought-responsi ve element (CRT/DRE) DNA regulatory element, Increased expression of A rabidopsis CBF1, a transcriptional activator that binds to the CRT/DRE sequence, induced COR gene expression and increased the freezing tole rance of nonacclimated Arabidopsis plants, We conclude that CBF1 is a likely regulator of the cold acclimation response, controlling the lev el of COR gene expression, which in turn promotes tolerance to freezin g.