Exploring the plasticity of lignification
department or school: Forestry, Faculty of
data provider: DSpace
degree campus: UBCV
creator: Mottiar, Yaseen
issued: 2021-08-23T20:25:39Z
issued: 2021
related degree: Doctor of Philosophy - PhD
degree grantor: University of British Columbia
description: Lignin is a phenolic polymer found predominantly in the secondary cell walls of vascular plants where it contributes to water transport, mechanical support, and plant defence. The occurrence, composition, and structure of lignin vary widely between cell types, throughout development, in response to stress, and across plant lineages. In addition to the hydroxycinnamate-derived monolignols, an array of non-canonical monomers occurs in lignin, clearly illustrating that the molecular processes underpinning lignin formation are highly flexible. This innate plasticity enables the rational design of lignins with predetermined structures and physicochemical properties. Given the biological importance of lignin and the industrial significance of plant biomass, this dissertation explores several promising areas of research in cell wall biology, plant biochemistry, and lignin engineering. The shikimate and aromatic amino acid pathways are crucial metabolic gatekeepers that lie upstream of lignin biosynthesis. In this work, chorismate was studied as an important branchpoint metabolite and evidence was uncovered for redundancy of chorismate mutase isomers in poplar (Populus trichocarpa). Next, a lignin engineering strategy that exploits this important branchpoint was developed. Introduction of a bacterial chorismate pyruvate lyase into transgenic hybrid poplar (Populus alba × grandidentata) was used to divert carbon flux away from phenylpropanoid biosynthesis, leading to lignin with more alkali-labile p-hydroxybenzoate pendent groups. In commelinid monocots, p-coumarate occurs analogously as lignin acylations. The discovery of these moieties in the lignin of kenaf (Hibiscus cannabinus), a eudicot species, represents a new example of convergent evolution and provides a useful tool for lignin engineering. Finally, lignification was studied in eastern leatherwood (Dirca palustris) as the woody stems of this native shrub are exceptionally flexible. In addition to an unusual composit…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/79410
note: EXPLORING THE PLASTICITY OF LIGNIFICATION by Yaseen Mottiar B.Sc., University of Ottawa, 2008 B.A.Sc., University of Ottawa, 2008 M.Sc., University of Toronto, 2012 A thesis submitted in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY in THE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES (Forestry) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) August 2021 © Yaseen Mottiar, 2021 ii The following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, the dissertation entitled: Exploring the plasticity of lignification submitted by Yaseen Mottiar in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Forestry Examining Committee: Shawn D. Mansfield, Department of Wood Science Research Supervisor Robert D. Guy, Department of Forest and Conservation Sciences Supervisory Committee Member A. Lacey Samuels, Department of Botany Supervisory Committee Member Joerg C. Bohlmann, Michael Smith Laboratories University Examiner Michael K. Deyholos, University of British Columbia – Okanagan University Examiner Jacqueline Grima-Pettenati, University of Toulouse III, France External Examiner Additional Supervisory Committee Member: Simone D. Castellarin, Wine Research Centre Supervisory Committee Member iii Abstract Lignin is a phenolic polymer found predominantly in the secondary cell walls of vascular plants where it contributes to water transport, mechanical support, and plant defence. The occurrence, composition, and structure of lignin vary widely between cell types, throughout development, in response to stress, and across plant lineages. In addition to the hydroxycinnamate-derived monolignols, an array of non-canonical monomers occurs in lignin, clearly illustrating that the molecular processes underpinning lignin formation are highly flexible. This innate plasticity enables the rational design of lignins with predetermined structures and physicochemi…
has type: Thesis/Dissertation
date issued: 2021-11
is shown at: 10.14288/1.0401500
language: eng
degree discipline: Forestry
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
contributor: Mansfield, Shawn D., 1969-
type: Text
identifier URI: http://hdl.handle.net/2429/79410