9307348 Thomashow Plants have evolved mechanisms that enable them to acclimate to, and survive, a variety of environmental stresses. Understanding how these mechanisms operate is fundamental to our knowledge of biological adaptation and may suggest novel approaches to improve the environmental stress tolerance of important crop and horticultural plant species. The primary interest of this award is in understanding the molecular basis of cold acclimation, the process whereby plants increase in freezing tolerance in response to low nonfreezing temperatures. Most of our work is with the small flowering plant Arabidopsis. It has been shown that Arabidopsis is capable of cold acclimating and that changes in gene expression occur during the cold acclimation process. A major goal now is to determine whether the cor (cold-regulated) genes have critical roles in freezing tolerance or some other aspect of low temperature survival. To address these issues, Dr. Thomashow and his colleagues have isolated cDNA and/or genomic clones for five Arabidopsis cor genes. The initial characterization suggests that certain of these genes may encode cryoprotective polypeptides. Many of the proposed experiments are directed at testing this hypothesis. In addition, experiments are proposed that will increase our knowledge of the magnitude and nature of the changes in gene expression that occur during cold acclimation. Taken together, these studies should not only add to our understanding of how plants acclimate to low temperature, but may also result in the identification of genes that can be used to manipulate the freezing and/or chilling tolerance of plants. ***
