THE ORGANIZATION OF THE CBF TRANSCRIPTIONAL ACTIVATOR PROTEIN ENCODING GENES IN TOMATO

Department of Horticulture and Crop Science,1680 Madison Avenue,The Ohio State University/OARDC,Wooster OH 44691

Low temperatures play a major determining factor in defining the geographical regions in which any given plant can successfully be grown. Yet plants have adopted strategies that allow them to survive in most geographical regions. One such strategy is cold acclimation, the biological phenomenon in which plants are able to increase their maximal level of freezing tolerance subsequent to a period of low, non-freezing temperature exposure. Integral to the cold acclimation process are the CBF family of transcriptional activator proteins. As first demonstrated in Arabidopsis thaliana the CBFs function by binding to the CRT/DRE, a low temperature and dehydration responsive DNA sequence element present in the promoter regions of many low-temperature induced Arabidopsis genes, and activating the expression of the contiguous gene's coding region. To explore the possibility that the CBFs perform a similar role in other plants, we have extended our investigations beyond Arabidopsis. Initial searches of the plant EST databases using the Blast algorithm indicated that CBF sequence homologs are present in many diverse plant taxa, including plants that are capable of cold acclimating and those that are unable to cold acclimate. Here we present our progress in which we have begun a molecular characterization of the structure and function of the genes encoding the CBFs in tomato.