Characterization and Environmental Regulation of a 24 kDa Cornus sericea Dehydrin-like Protein and its Relationship to Freeze-Tolerance (The Seminar, "Stresses and Responses and Adaptation of Living Organisms : Molecular and Cellular Mechanisms and its Application")

Abstract

Using the extremely freeze-tolerant woody shrub C. sericea as a model system, we investigated the association of xylem proteins to cold acclimation. We identified a predominant 24 kDa dehydrin-like protein that accumulated during cold acclimation, raised a polyclonal antibody and screened a cDNA expression library to search for related genes. In controlled environment conditions, we identified and deciphered the mode of regulation for the 24 kDa protein by manipulating abiotic factors and monitoring subsequent physiological and molecular effects. With immunolocalization techniques, we clarified the subcellular localization of 24 kDa-like proteins in an effort to provide insight into a potential biological role. To assess the proposed role of dehydrins to freeze induced desiccation (caused by extracellular ice formation), we characterized freezing behavior within 30 Cornus species into classifications of either supercooling or non-supercooling behaviors. Subsequent comparisons of total xylem protein blot analysis determined that 24 kDa-like proteins were not limited to species that display non-supercooling behavior, nor to those species that are extremely freeze-tolerant.