Functional analysis of KNOTTED-like homeobox and OVATE family proteins involved in secondary cell wall development in Arabidopsis
department or school: Science, Faculty of
department or school: Botany, Department of
data provider: DSpace
degree campus: UBCV
creator: Wang, Shumin
issued: 2019-10-31T07:00:00Z
issued: 2018
related degree: Doctor of Philosophy - PhD
degree grantor: University of British Columbia
description: The formation of plant secondary cell walls requires a complex network of transcriptional regulation, culminating in a coordinated suite of biosynthetic genes depositing walls, in a spatial and temporal fashion. The transcription factor KNOTTED ARABIDOPSIS THALIANA7 (KNAT7) is a Class II KNOTTED1-like homeobox (KNOX2) gene, that acts as a negative regulator of secondary cell wall biosynthesis in interfascicular fibers. Previously, members of Ovate Family Proteins (OFP1 and OFP4), were shown to interact with KNAT7 to negatively regulate wall formation. However, the function of other closely related KNOX2 and OFP genes in secondary wall formation remains unclear. Herein, I showed that knat3knat7 double mutants possess an enhanced irregular xylem (irx) phenotype relative to single mutants, and decreased interfascicular fiber cell wall thickness. Additionally, unlike the increased lignin content characteristic of knat7 mutants, knat3knat7 had no change in lignin content, while the monomeric lignin composition was substantially reduced relative to the wild-type plants. In contrast, KNAT3 overexpression resulted in thicker interfascicular fiber secondary walls, suggesting a positive regulation of KNAT3 in wall development. A thorough examination of OFP mutants showed that none of the single mutants revealed any wall defects, including ofp4, which was previously shown to interact with KNAT7. However, they do display leaf phenotypes. In contrast, plants overexpressing OFP isoforms consistently exhibited cell swelling, disordered microtubules, and dark-grown de-etiolated phenotypes, resembling phenotypes common to brassinosteroid deficient mutants. Using yeast two-hybrid and bimolecular fluorescence complementation assays, I identified two genes that interacted with OFP4, NAP1;1 and NAP1;2, members of the Nucleosome Assembly Protein 1 (NAP1) family. Higher-order, loss-of-function NAP1 and OFP mutants also exhibit altered cotyledon shape and a reduced cotyledon width:length r…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/65727
note: FUNCTIONAL ANALYSIS OF KNOTTED-LIKE HOMEOBOX AND OVATE FAMILY PROTEINS INVOLVED IN SECONDARY CELL WALL DEVELOPMENT IN ARABIDOPSIS by Shumin Wang M.Sc., Nanjing Agricultural University, 2011 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES (BOTANY) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) April 2018 © Shumin Wang, 2018 ii Abstract The formation of plant secondary cell walls requires a complex network of transcriptional regulation, culminating in a coordinated suite of biosynthetic genes depositing walls, in a spatial and temporal fashion. The transcription factor KNOTTED ARABIDOPSIS THALIANA7 (KNAT7) is a Class II KNOTTED1-like homeobox (KNOX2) gene, that acts as a negative regulator of secondary cell wall biosynthesis in interfascicular fibers. Previously, members of Ovate Family Proteins (OFP1 and OFP4), were shown to interact with KNAT7 to negatively regulate wall formation. However, the function of other closely related KNOX2 and OFP genes in secondary wall formation remains unclear. Herein, I showed that knat3knat7 double mutants possess an enhanced irregular xylem (irx) phenotype relative to single mutants, and decreased interfascicular fiber cell wall thickness. Additionally, unlike the increased lignin content characteristic of knat7 mutants, knat3knat7 had no change in lignin content, while the monomeric lignin composition was substantially reduced relative to the wild-type plants. In contrast, KNAT3 overexpression resulted in thicker interfascicular fiber secondary walls, suggesting a positive regulation of KNAT3 in wall development. A thorough examination of OFP mutants showed that none of the single mutants revealed any wall defects, including ofp4, which was previously shown to interact with KNAT7. However, they do display leaf phenotypes. In contrast, plants overexpressing OFP isoforms consistently exhibited cell swelling, disordered microtubul…
has type: Thesis/Dissertation
date issued: 2018-09
is shown at: 10.14288/1.0366123
language: eng
degree discipline: Botany
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
type: Text
identifier URI: http://hdl.handle.net/2429/65727