Identifying novel genes involved in the synthesis, secretion and modification of cell wall components in the seed coat of «Arabidopsis thaliana»

Plant cells are encased within a complex polysaccharide wall that not only strengthens the plant, but also has key roles in plant growth, cell differentiation, and defence. The plant cell wall is comprised of a network of cellulose microfibrils interconnected by hemicelluloses; this framework is em...

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Main Author: Arsovski, Andrej Adam
Other Authors: Tamara Western (Supervisor)
Format: Others
Language:en
Published: McGill University 2010
Subjects:
Online Access:http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=92159
id ndltd-LACETR-oai-collectionscanada.gc.ca-QMM.92159
record_format oai_dc
collection NDLTD
language en
format Others
sources NDLTD
topic Biology - Molecular
spellingShingle Biology - Molecular
Arsovski, Andrej Adam
Identifying novel genes involved in the synthesis, secretion and modification of cell wall components in the seed coat of «Arabidopsis thaliana»
description Plant cells are encased within a complex polysaccharide wall that not only strengthens the plant, but also has key roles in plant growth, cell differentiation, and defence. The plant cell wall is comprised of a network of cellulose microfibrils interconnected by hemicelluloses; this framework is embedded in a more soluble pectin matrix. This dynamic structure is under continual modification during plant growth and development, and its synthesis and modification requires the activity of a myriad of enzymes. Recent research has provided insight into how plants manufacture and regulate the cell wall during development, but much remains unknown. The mucilage secretory cells (MSCs) of Arabidopsis thaliana are used as a model to discover novel genes involved in the synthesis, secretion and modification of cell wall components, particularly pectin. These cells synthesize copious amounts of pectinaceous mucilage during development and, upon hydration of the desiccated seed, this mucilage rapidly swells, bursts from the MSCs and surrounds the seed in a gelatinous capsule. The patchy (pty)/beta-xylosidase1(bxl1) mutant has a peculiar phenotype where mucilage release is patchy and slow, and mutant seeds are delayed in germination. Cloning of the mutant locus revealed a lesion in an encoded bifunctional β-xylosidase/α-arabinofuranosidase. Chemical and immunological analyses indicate an increase in 1,5-linked arabinans, suggesting the action of AtBXL1 is required for the trimming of these chains to allow correct mucilage release. In addition to the study of AtBXL1, an enhancer/suppressor screen of the mum4 reduced mucilage mutant was performed in order to identify novel genes involved in mucilage secretory cell differentiation. The screen identified six novel mutants named mum enhancer (men) 1-6. Characterization of men mum4 double mutants revealed two distinct groups, those that produced similar amounts of mucilage to mum4 but failed to release it (men2, 6), and === Les cellules végétales sont encastrées dans une paroi de polysaccharide complexe qui non seulement renforce la plante mais aussi agit de façon cruciale dans les mécanismes de croissance, de différentiation cellulaire et de défense. La paroi des cellules végétales consiste en un réseau de microfibrilles de cellulose connectées par des hemicelluloses. Ce réseau est encastré dans une matrice de pectine plus solubilisable. Cette structure dynamique est en modification perpétuelle pendant le développement et la croissance de la plante. Ces changements et sa synthèse engage l'action d'une myriade d'enzymes. Des études récentes ont données de nouvelles perspectives sur comment les plantes produisent et régulent leur paroi cellulaire pendant le développement cependant beaucoup reste à découvrir. Les cellules sécréteuses de mucilage (MSCs) d'Arabidopsis thaliana sont utilisées comme modèles pour la découverte de nouveaux gène impliqués dans la synthèse, sécrétion et la modification des composants de la paroi cellulaire, particulièrement la pectine. Ces cellules synthétisent de grandes quantité de mucilage pectiné durant le développement et, après hydration de la graine disséquée, celui-ci gonfle rapidement, jaillit des MSCs entourant la graine d'une capsule gélatineuse. Le mutant patchy (pty)/beta-xylosidase1(bxl1) présente un phénotype particulier où le relargage est épars et lent, ces graines présentent aussi un retard dans la germination. Le clonage du locus muté a révélé une lésion dans la β-xylosidase/α-arabinofuranosidase bifonctionelle transcrite. Les analyses chimique et immunologique ont indiquées une augmentation des 1,5-linked arabinans suggérant que l'action de BXL1 est requise pour l'hydrolyse de ces chaines permettant un bon relargage du mucilage. En parallèle de cette étude, un screen des enhancers/suppresseurs du mutant au mucilage réduit mum4 dans l'intention d'identifier des nouveaux gènes imp
author2 Tamara Western (Supervisor)
author_facet Tamara Western (Supervisor)
Arsovski, Andrej Adam
author Arsovski, Andrej Adam
author_sort Arsovski, Andrej Adam
title Identifying novel genes involved in the synthesis, secretion and modification of cell wall components in the seed coat of «Arabidopsis thaliana»
title_short Identifying novel genes involved in the synthesis, secretion and modification of cell wall components in the seed coat of «Arabidopsis thaliana»
title_full Identifying novel genes involved in the synthesis, secretion and modification of cell wall components in the seed coat of «Arabidopsis thaliana»
title_fullStr Identifying novel genes involved in the synthesis, secretion and modification of cell wall components in the seed coat of «Arabidopsis thaliana»
title_full_unstemmed Identifying novel genes involved in the synthesis, secretion and modification of cell wall components in the seed coat of «Arabidopsis thaliana»
title_sort identifying novel genes involved in the synthesis, secretion and modification of cell wall components in the seed coat of «arabidopsis thaliana»
publisher McGill University
publishDate 2010
url http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=92159
work_keys_str_mv AT arsovskiandrejadam identifyingnovelgenesinvolvedinthesynthesissecretionandmodificationofcellwallcomponentsintheseedcoatofarabidopsisthaliana
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spelling ndltd-LACETR-oai-collectionscanada.gc.ca-QMM.921592014-02-13T04:08:50ZIdentifying novel genes involved in the synthesis, secretion and modification of cell wall components in the seed coat of «Arabidopsis thaliana»Arsovski, Andrej AdamBiology - MolecularPlant cells are encased within a complex polysaccharide wall that not only strengthens the plant, but also has key roles in plant growth, cell differentiation, and defence. The plant cell wall is comprised of a network of cellulose microfibrils interconnected by hemicelluloses; this framework is embedded in a more soluble pectin matrix. This dynamic structure is under continual modification during plant growth and development, and its synthesis and modification requires the activity of a myriad of enzymes. Recent research has provided insight into how plants manufacture and regulate the cell wall during development, but much remains unknown. The mucilage secretory cells (MSCs) of Arabidopsis thaliana are used as a model to discover novel genes involved in the synthesis, secretion and modification of cell wall components, particularly pectin. These cells synthesize copious amounts of pectinaceous mucilage during development and, upon hydration of the desiccated seed, this mucilage rapidly swells, bursts from the MSCs and surrounds the seed in a gelatinous capsule. The patchy (pty)/beta-xylosidase1(bxl1) mutant has a peculiar phenotype where mucilage release is patchy and slow, and mutant seeds are delayed in germination. Cloning of the mutant locus revealed a lesion in an encoded bifunctional β-xylosidase/α-arabinofuranosidase. Chemical and immunological analyses indicate an increase in 1,5-linked arabinans, suggesting the action of AtBXL1 is required for the trimming of these chains to allow correct mucilage release. In addition to the study of AtBXL1, an enhancer/suppressor screen of the mum4 reduced mucilage mutant was performed in order to identify novel genes involved in mucilage secretory cell differentiation. The screen identified six novel mutants named mum enhancer (men) 1-6. Characterization of men mum4 double mutants revealed two distinct groups, those that produced similar amounts of mucilage to mum4 but failed to release it (men2, 6), andLes cellules végétales sont encastrées dans une paroi de polysaccharide complexe qui non seulement renforce la plante mais aussi agit de façon cruciale dans les mécanismes de croissance, de différentiation cellulaire et de défense. La paroi des cellules végétales consiste en un réseau de microfibrilles de cellulose connectées par des hemicelluloses. Ce réseau est encastré dans une matrice de pectine plus solubilisable. Cette structure dynamique est en modification perpétuelle pendant le développement et la croissance de la plante. Ces changements et sa synthèse engage l'action d'une myriade d'enzymes. Des études récentes ont données de nouvelles perspectives sur comment les plantes produisent et régulent leur paroi cellulaire pendant le développement cependant beaucoup reste à découvrir. Les cellules sécréteuses de mucilage (MSCs) d'Arabidopsis thaliana sont utilisées comme modèles pour la découverte de nouveaux gène impliqués dans la synthèse, sécrétion et la modification des composants de la paroi cellulaire, particulièrement la pectine. Ces cellules synthétisent de grandes quantité de mucilage pectiné durant le développement et, après hydration de la graine disséquée, celui-ci gonfle rapidement, jaillit des MSCs entourant la graine d'une capsule gélatineuse. Le mutant patchy (pty)/beta-xylosidase1(bxl1) présente un phénotype particulier où le relargage est épars et lent, ces graines présentent aussi un retard dans la germination. Le clonage du locus muté a révélé une lésion dans la β-xylosidase/α-arabinofuranosidase bifonctionelle transcrite. Les analyses chimique et immunologique ont indiquées une augmentation des 1,5-linked arabinans suggérant que l'action de BXL1 est requise pour l'hydrolyse de ces chaines permettant un bon relargage du mucilage. En parallèle de cette étude, un screen des enhancers/suppresseurs du mutant au mucilage réduit mum4 dans l'intention d'identifier des nouveaux gènes impMcGill UniversityTamara Western (Supervisor)2010Electronic Thesis or Dissertationapplication/pdfenElectronically-submitted theses.All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated.Doctor of Philosophy (Department of Biology) http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=92159