Status of the methylome in Solanum tuberosum tubers treated with sprout inhibitor 1,4-dimethylnaphthalene

Open Access
- Author:
- Eiss, Emily
- Area of Honors:
- Biology (Behrend)
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Michael A Campbell, Thesis Supervisor
Michael A Campbell, Thesis Honors Advisor
Adam Martin Simpson, Faculty Reader - Keywords:
- epigenetics
tubers
potato
potatoes
solanum tuberosum
methylation
genetics - Abstract:
- The success of the potato industry depends heavily on the storage of the tubers; if potatoes sprout while in storage, the stock is ruined for commercial sale. For this reason, the industry relies on aerosol sprout inhibitors to prevent sprout growth. One such inhibitor is 1,4-dimethylnaphthalene, or DMN. It is found naturally in potatoes and thus is considered a more natural sprout inhibitor, but it is unknown how DMN prevents growth. This study considers epigenetics as a possible mechanism of sprout inhibition, particularly in the form of DNA methylation. DNA methylation is the covalent attachment of a methyl group (-CH3), particularly to cytosines, that inhibits expression of genes downstream of the methylation. Genomic DNA from meristem tissue of potatoes was isolated before undergoing bisulfite conversion and sequencing at Beijing Genomics Institute. Bisulfite conversion elucidates methylation data by chemical conversion of non-methylated cytosines into uracil, ultimately providing a final sequence wherein all remaining cytosines indicate a methylated cytosine. These data were analyzed using the bisulfite sequencing analysis software “bismark” and aligned with an annotated potato genome through the website Comparative Genomics (CoGe). Methylation rates and locations were compared between different treatments, and the genes identified as being under possible methylation control were referenced to previous gene expression data. The genes identified were not consistently up- or downregulated after exposure to DMN, so we conclude that DMN inhibits sprout growth through another cellular process that also alters DNA methylation and gene expression as a result.