Date of Award

12-2008

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Genetics

Advisor

Moore, Brandon

Committee Member

Marcotte, Jr. , William

Committee Member

Smith , Kerry

Abstract

Identifying the initial sugar sensing and response activating mechanisms in plants has been difficult due to the dual functions of sugars as nutrients and as signaling molecules. In this study, we have examined transcript expression and promoter features of different genes encoding proteins for actin remodeling that have been implicated as targets of plant glucose signaling. Using Reverse Transcription PCR analysis, we confirmed that expression of two actin-associated genes, actin depolymerizing factor 9 (ADF9) and actin related protein 8 (ARP8), are repressed following a short-term glucose treatment of Arabidopsis thaliana seedlings. Glucose did not repress the expression of other ADF and ARP gene family members. The cis-acting promoter elements of both gene families were evaluated using the PLACE database. This analysis indicated that the ARP8 promoter has a unique signature motif, a four amylase box 1 repeat, that might
account for the observed glucose dependent repression response. A unique response element motif was not readily identified in the predicted promoter region of ADF9. To further define possible sugar response elements, the predicted promoters of ADF9 and ARP8 were cloned as luciferase fusions in a plant expression vector. However, by transient expression assay, the cloned constructs were not active under different experimental conditions. Identifying the functionally active sugar response elements in the predicted promoter regions of genes that are targets of glucose signaling will improve our understanding of this regulatory process.

Included in

Genetics Commons

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