Investigating the role of sucrose phosphate synthase and hexokinase in carbon sink strength.
department or school: Forestry, Faculty of
data provider: DSpace
degree campus: UBCV
creator: Lazarova, Sofiya
issued: 2015-10-24T06:52:03
issued: 2015
related degree: Master of Science - MSc
degree grantor: University of British Columbia
description: The production, transport and assimilation of organic carbon ultimately drive the growth of plants. In this work, two enzymes, Sucrose Phosphate Synthase (SPS) and Hexokinase (HXK), prominent in their role of carbon production in the form of sucrose at the source, have been examined for their role at the sink, where carbon is assimilated. It has been postulated that the presence of sucrose-forming enzymes in the sink serves a function to reform sucrose from apoplastic cleavage or partake in a “futile” cycle of sucrose cleavage and such that small changes in metabolite enable large changes in sink carbon strength. In order to determine if SPS is involved in carbon sink strength, A. thaliana TDNA insertional lines and P. trichocarpa RNAi stem and developing xylem with decreased SPS transcript expression were analyzed. It was determined that loss of SPS transcript generally increases soluble sugars: sucrose, glucose and fructose, in the leaf and stem as well as starch in the leaf. Structural carbohydrates were generally unaffected and Klason soluble lignin decreased. Similarly, A. thaliana TDNA insertional lines with decreased HXK transcript expression were utilized to determine the role of HXK using stem tissue as a carbon sink model. Soluble sugars mainly increased in the leaf of athxk3 TDNA insertional line whereas starch increased in both leaf and stem of the same line. Interestingly, structural carbohydrate levels of the cell wall were perturbed in HXK TDNA insertional lines. The results were found to be consistent with the postulated roles of SPS and HXK that predict a function in sucrose formation from apoplastic cleavage, which allows for fine-tuning of major intracellular metabolites and adjustment of sink strength.
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/55000
note: INVESTIGATING THE ROLE OF SUCROSE PHOSPHATE SYNTHASE AND HEXOKINASE IN CARBON SINK STRENGTH by Sofiya Lazarova B.Sc. (Hons.), The University of Toronto, 2012 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES (Forestry) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) October 2015 © Sofiya Lazarova, 2015 ii Abstract The production, transport and assimilation of organic carbon ultimately drive the growth of plants. In this work, two enzymes, Sucrose Phosphate Synthase (SPS) and Hexokinase (HXK), prominent in their role of carbon production in the form of sucrose at the source, have been examined for their role at the sink, where carbon is assimilated. It has been postulated that the presence of sucrose-forming enzymes in the sink serves a function to reform sucrose from apoplastic cleavage or partake in a “futile” cycle of sucrose cleavage and such that small changes in metabolite enable large changes in sink carbon strength. In order to determine if SPS is involved in carbon sink strength, A. thaliana TDNA insertional lines and P. trichocarpa RNAi stem and developing xylem with decreased SPS transcript expression were analyzed. It was determined that loss of SPS transcript generally increases soluble sugars: sucrose, glucose and fructose, in the leaf and stem as well as starch in the leaf. Structural carbohydrates were generally unaffected and Klason soluble lignin decreased. Similarly, A. thaliana TDNA insertional lines with decreased HXK transcript expression were utilized to determine the role of HXK using stem tissue as a carbon sink model. Soluble sugars mainly increased in the leaf of athxk3 TDNA insertional line whereas starch increased in both leaf and stem of the same line. Interestingly, structural carbohydrate levels of the cell wall were perturbed in HXK TDNA insertional lines. The results were found to be consistent with the postulated roles of SPS and HXK t…
has type: Thesis/Dissertation
date issued: 2015-11
is shown at: 10.14288/1.0166766
language: eng
degree discipline: Forestry
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivs 2.5 Canada
rights URI: http://creativecommons.org/licenses/by-nc-nd/2.5/ca/
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/55000