| The native grape, Vitis riparia, enters dormancy to survive winter conditions. The overwintering buds then require chilling hours before they can grow. Bud tissue was collected after 0, 500, 1000, 1500, and 2000 hours of chilling. Three-node cuttings were evaluated to monitor depth of dormancy. Complete bud break occurred after 1500 chilling hours. However, the rate of bud break was significantly faster after 2000 chilling hours. Microarray data analysis of the 1000, 1500, and 2000 hour time points compared to 500 chilling hours revealed an increasing number of genes significantly differentially expressed with increasing chill accumulation. A core group of genes were down-regulated at all time points. Genes were up-regulated only at 2000 hours of chilling. The majority of genes down-regulated were involved in metabolism and cell defense and stress response. Up-regulated genes were involved in metabolism and genetic information processing. Real-time PCR verified 86% of the candidate genes. |
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