Date of Award
2006
Degree Type
Thesis
Degree Name
Master of Science
Program
Biology
Supervisor
Dr. Denis P. Maxwell
Second Advisor
Dr. Susanne Kohalmi
Third Advisor
Dr. Charles G. Trick
Abstract
The focus of this project is the initial characterization of a recently isolated stress-induced gene from tobacco (Nicotiana tobacum}. Analysis of the predicted amino acid sequence of this gene shows that it shares the highly conserved carboxy-terminal motifs common to members of the GRAS family of proteins. Because of this similarity, the gene is denoted NtGRAS1. Transcript abundance was found to be induced in tobacco BY-2 cells by antimycin A, H2O2, salicylic acid, L-cysteine and sodium nitroprusside. All treatments were found to raise intracellular reactive oxygen levels. Inhibition of protein kinase and phosphatase action revealed that reversible phosphorylation is required for the stress-induced upregulation of NtGRAS1. In soil-grown tobacco plants, NtGRASl was constitutively expressed only in roots while expression was strongly induced in leaf tissue following antimycin A treatment or pathogen infection. Members of the GRAS family are implicated in the regulation of transcription and this function for NtGRASl is supported by the finding that an NtGRASl-green fluorescence fusion protein localized to the nucleus.
Recommended Citation
Czikkel, Beatrix E., "CHARACTERIZATION OF NtGRAS1, A NOVEL STRESS-INDUCED MEMBER OF THE GRAS FAMILY" (2006). Digitized Theses. 4910.
https://ir.lib.uwo.ca/digitizedtheses/4910