| Autopolyploidy and tuberization are characteristics rarely found in the plant kingdom, and are nearly nonexistent outside of plants. However, these features are commonly found throughout the genus Solanum. In this thesis, I have used gene expression profiling methods to characterize the transcriptional changes that are associated with these traits in Solanum. A series of microarray experiments were performed to test the transcriptional differences in a synthetic autopolyploid series from Solanum consisting of monoploid (1x), diploid (2x), and tetraploid (4x) plants. Three gene families were consistently found to be upregulated with ploidy in growing leaf tissues: ribosomal protein genes, histories, and cyclins. Several other genes were also found to be upregulated and downregulated with ploidy, although most gene expression changes were relatively small. Furthermore, gene expression profiling was investigated throughout a series of potato tuber developmental stages. The main work presented here focuses on patatin genes, the main tuber storage protein family. Northern blotting and ChIP-real-time PCR were used in combination to show that the upregulation of patatin genes in early tuber tissue is accompanied by an increase in nucleosome acetylation at patatin loci. 3' RACE was used to profile the expression of subsets and individual patatin genes. Changes were observed in the 3' UTR structure of patatin genes during different developmental stages. However, one dominant patatin gene group appears to be the most prevalent during all stages of tuber development. The full coding sequence of this particular gene has been identified. |
