Glutathione Dynamics in Arabidopsis Seed Development and Germination

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dc.contributor.authorSumugat, Mae Rose S.en
dc.contributor.committeechairWelbaum, Gregory E.en
dc.contributor.committeememberShulaev, Vladimiren
dc.contributor.committeememberGrene, Ruthen
dc.contributor.departmentHorticultureen
dc.date.accessioned2014-03-14T20:50:42Zen
dc.date.adate2004-12-29en
dc.date.available2014-03-14T20:50:42Zen
dc.date.issued2004-12-09en
dc.date.rdate2004-12-29en
dc.date.sdate2004-12-23en
dc.description.abstractSeed desiccation and germination have great potential for oxidative stress. Glutathione, one of the most abundant antioxidants in plant cells, is a crucial to the plant's defense mechanisms. To better understand glutathione's responses during these two stages, we examined its dynamics in wildtype Arabidopsis seeds and in a transgenic line containing an antisense glutathione reductase2 (anGR2) cDNA insert. Seeds from the two genotypes were compared morphologically. Glutathione levels in maturing and germinating seeds were measured by HPLC, and GR activity by native PAGE. Cytosolic glutathione was measured in situ by confocal laser scanning microscopy. Stress in the form of natural and accelerated ageing, and germination at high and low temperature and at low water potential was applied to both WT and anGR2 seeds to test vigor. Results show similar glutathione levels and GR activity (except during late imbibition) in WT and anGR2. In both genotypes, GSH/GSSG ratio increased and GR activity decreased during seed maturation. During imbibition, the glutathione pool becomes very reduced (<1% GSSG) and in WT seeds, GSH levels increase mostly by GSSG recycling. Cytosolic GSH in embryonic epidermal cells was estimated to be 1.1-1.6 mM. AnGR2 seeds aged faster, and were less tolerant of heat and drought stress than WT. Accumulation of glutathione during maturation indicated that glutathione is a major antioxidant in the seed during storage. Changes in GSH levels during imbibition coincided with ROS production during radicle protrusion. Under stress conditions, anGR2 seeds showed lower vigor, indicating perturbations in the ROS scavenging systems particularly GR2.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-12232004-103334en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-12232004-103334/en
dc.identifier.urihttp://hdl.handle.net/10919/36420en
dc.publisherVirginia Techen
dc.relation.haspartTHESIS.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectglutathione reductaseen
dc.subjectseed developmenten
dc.subjectseed germinationen
dc.subjectglutathioneen
dc.subjectArabidopsis thalianaen
dc.titleGlutathione Dynamics in Arabidopsis Seed Development and Germinationen
dc.typeThesisen
thesis.degree.disciplineHorticultureen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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