Submitted to: Plant Dormancy Symposium
Publication Type: Abstract Only
Publication Acceptance Date: 6/30/1999
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: The seasonal process of cold acclimation in woody plants allows them to tolerate and survive freezing. Additionally, temperate woody plants undergo a period of dormancy where growth is arrested. Transitions (onset and loss) in dormancy and cold acclimation partially overlap, making it difficult to associate physiological and molecular changes specifically with one or the other phenological events. To overcome this problem, researchers have devised several different approaches. One of these strategies has been the use of sibling genotypes of peach segregating for deciduous (dormant) and evergreen (non-dormant) habits. These genotypes exhibit a significant difference in their ability to cold acclimate while the apical meristems of the evergreen genotype do not form buds or exhibit endodormancy. This system has allowed us to identify several seasonally- regulated proteins that may be specifically associated with either dormancy yor cold acclimation. We have characterized a 60 kDa dehydrin (PCA60) extensively and cloned the gene (ppdhn1) coding for this protein. The protein is both qualitatively and quantitatively associated with cold acclimation within and between genotypes. We have also identified several other proteins (5, 16, and 19 kDa) in peach that due to their seasonal expression and abundance would be typically classified as storage proteins. Based on the partial or entire sequence of these proteins or genes, however only one, the 16 kDa protein, may serve solely as a nitrogen reserve. The 5 kDa protein is a defensin (a family of highly antifungal proteins) while the 19 kDa protein is highly homologous to pathogenesis-related and ABA- responsive proteins. The 19 kDa and defensin are also fruit ripening related.