The impact of delayed nodule senescence by tissue-specific cysteine protease inhibitor expression in soybean [Glycine max (L.) Merr.] development and response to abiotic stress

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dc.contributor.advisor Vorster, Barend Juan
dc.contributor.postgraduate Mathibela, Elizabeth Ofentse
dc.date.accessioned 2021-08-11T11:00:18Z
dc.date.available 2021-08-11T11:00:18Z
dc.date.created 2021
dc.date.issued 2021
dc.description Dissertation (MSc (Plant Science))--University of Pretoria, 2021. en_ZA
dc.description.abstract Soybean yields are negatively affected by both natural and stress induced senescence of nodules since it limits nitrogen supply to the plants resulting in nitrogen deficiency. Senescence is due to accelerated and unregulated activity of proteases, specifically cysteine proteases. In this study, transgenic soybean plants expressing a cysteine protease inhibitor (OC-I) specifically in root nodules were characterized under natural and stress-induced tolerance. The hypothesis being that OC-I will delay nodule senescence resulting in prolonged nitrogen supply which will delay leaf degradation for nutrient remobilization thus leading to improved growth. Unlike ectopic expression in previous studies, tissue-specific expression did not lead to reduced growth of the transgenic lines as compared to wild type under normal conditions. Transgenic lines maintained significantly higher photosynthetic machinery (chlorophyll) as well reduced oxidative damage (hydrogen peroxide and malondialdehyde) under natural and stress induced-conditions senescence. The reduced oxidative damage was due to improved antioxidant pool (GST, POD, CAT), osmoprotectant and protective pigment accumulation (proline, anthocyanin, carotene). Ureide content accumulation in root nodules indicated significant nitrogen fixation in transgenic lines as compared to wild type. Metabolite accumulation was also investigated to understand partitioning patterns of the plants. Accumulated data suggest the involvement of OC-I in senescence tolerance. en_ZA
dc.description.availability Unrestricted en_ZA
dc.description.degree MSc (Plant Science) en_ZA
dc.description.department Plant Science en_ZA
dc.description.sponsorship National Research Foundation (NRF) en_ZA
dc.description.sponsorship Haylett Trust Fund en_ZA
dc.identifier.citation * en_ZA
dc.identifier.other S2021 en_ZA
dc.identifier.uri http://hdl.handle.net/2263/81235
dc.language.iso en en_ZA
dc.publisher University of Pretoria
dc.rights © 2019 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.
dc.subject UCTD en_ZA
dc.subject Plant Science en_ZA
dc.title The impact of delayed nodule senescence by tissue-specific cysteine protease inhibitor expression in soybean [Glycine max (L.) Merr.] development and response to abiotic stress en_ZA
dc.type Dissertation en_ZA


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