Poster: Vegetative development
Abs #
333: Genetic regulation of the annual growth cycle of woody plants
Temperate woody plants have an adaptive mechanism for winter survival, which involves seasonal alternation between active shoot growth and vegetative dormancy. This annual growth cycle is closely timed with seasonal changes in daylength and temperature. As the first step toward understanding the molecular basis of this process in woody perennials, a series of transcriptional profiling experiments were carried out to identify batteries of genes whose expression patterns are closely associated with the annual growth cycle. Using monthly stem samples from field-grown poplar trees and samples from trees growing under differing controlled environment conditions (e.g., daylength and temperature), we identified a large number of genes that are differentially expressed during these different environmental conditions. For example, the genes involved in the pentose phosphate pathway and glycolysis were upregulated during winter months, indicating differential regulation of respiratory processes during the winter. Furthermore, our results showed that SD could modulate the cold signal in at least two different ways. First, SD could induce cold associated genes independent of actual cold temperatures, which also resulted in higher expression of the genes in cold temperatures than results from the cold signal alone. This day length mechanism for initiating cold-associated genes may buffer woody plants against warm weather during the fall. Second, the SD signal itself did not induce some of the genes associated with cold acclimation, but did enhance their expression in cold temperatures. This mechanism may help plants distinguish between unseasonably cold temperatures and cold temperatures associated with the normal cycling of seasons.
