ISHS Acta Horticulturae 560: IV International Symposium on In Vitro Culture and Horticultural Breeding
COLD ACCLIMATION AND DEVELOPMENT OF FREEZING AND DROUGHT TOLERANCE IN PLANTS |
| Authors: | E.T. Palva, A. Welling, S. Tähtiharju, I. Tamminen, T. Puhakainen, P. Mäkelä, R. Laitinen, C. Li, E. Helenius, M. Boije, K. Aspegren, O. Aalto, P. Heino |
| Keywords: | stress tolerance, cold hardiness, overwintering, signal transduction, gene expression, Arabidopsis, birch |
| Abstract:
Plant growth, productivity and distribution are severely limited by environmental stresses including drought, salinity and freezing, all of which disturb the water balance of the cell. Plants have evolved different adaptive strategies to alleviate the adverse effects of these abiotic stresses. In plant cold acclimation exposure to moderate stress (such as low nonfreezing temperatures) or to other environmental cues (such as drought or changes in photoperiod) triggers stress acclimation pathways leading to an increase in freezing tolerance. This acclimation is associated with expression of a number of stress response genes and subsequent metabolic and physiological alterations required for the enhanced stress tolerance. Elucidation of the signal pathways and components controlling the stress response regulons is one of the key areas plant stress research. A central theme of our research is to clarify how plants sense the environmental cues triggering cold acclimation and how these signals are transduced to the level of target gene expression. Two model systems are employed for our studies: Arabidopsis and birch. We use Arabidopsis to explore the low temperature triggered acclimation during the growing season typical to many temperate herbaceous species and birch for elucidating the mechanism of photoperiod controlled seasonal acclimation characteristic of woody species. Our recent work in Arabidopsis is focused on characterization of selected candidate signal components including putative channel proteins and protein phosphatases. In birch the initial work is focused on photoperiod sensing as well as characterization of the stress regulons by genomic approaches. Modulation of the key components of low temperature response pathways would allow engineering of plant stress tolerance. Metabolic engineering of osmoprotectant biosynthesis will also be discussed as one strategy to improve stress tolerance. | |
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