Molecular aspects of Vitis CBF gene activation
The 'Vitis' plant genus includes the wild, freezing tolerant ' V. riparia', and a freezing sensitive cultivar widely used in the viticulture industry, 'V. vinifera'. It has been shown that freezing tolerance is controlled through a signal casade known as the ' CBF' ('C-repeat binding factor') pathway in ' Arabidopsis'. The goal of this research was to start investigating how 'Vitis CBF' expression is regulated. 'In silico ' analyses and over expression in 'Arabidopsis' identified putative regulatory promoter elements, in particular for 'Vitis CBF1 ' and '4'. A dual luciferase pCAMBIA-based binary vector that allows a quantitative comparison of different promoters was successfully constructed. Using this vector, it was shown that a cluster of four elements on the 346bp promoter, and a MYC element on the 280 bp promoter appear to be necessary for induction of 'VrCBF4' at ambient temperature. A putative 'CBF'-expression regulating ICE transcription factor was cloned for future transactivation studies with the newly developed vector.