Molecular Genetics of Cold Acclimation in Higher Plants

This chapter discusses the molecular genetics of cold acclimation in higher plants. The chapter focuses primarily on the recent molecular genetic studies related to cold-acclimation-associated changes in the gene expression. These studies—although only in their infancy—have yielded significant results and suggest future areas of research. The chapter begins with an overview of the biochemistry of cold acclimation because this information is required for the discussion of potential cor gene function. Perhaps the most dramatic manifestation of cold acclimation or cold hardening is the increased freezing tolerance that occurs in many plant species. A number of biochemical changes are shown to occur in plants during cold acclimation. Common examples include alterations in lipid composition, the appearance of new isozymes, increased sugar and soluble protein content, and increased levels of proline and other organic acids. Some of these changes—such as the alterations in lipid composition—appear to have roles in bringing about the increased frost tolerance of acclimated plants. The biochemical, biophysical, and physiological changes that occur in plant cells during cold acclimation could be brought about by preexisting macromolecules and structure enzymes, structural proteins, lipids, and membranes that undergo changes in their physical properties at low temperatures.