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Proteases and protease inhibitors involved in plant stress response and acclimation
Thesis (PhD)--University of Pretoria, 2009.
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| Format: | Thesis |
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University of Pretoria
2013
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| _version_ | 1867613548037799936 |
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| access_status_str | Open Access |
| author2 | Kunert, Karl J. |
| author_browse | Kunert, Karl J. |
| author_facet | Kunert, Karl J. |
| collection | Thesis |
| dc_rights_str_mv | © University of Pretoria 2008 D557/ |
| description | Thesis (PhD)--University of Pretoria, 2009. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/24337 |
| institution | University of Pretoria (South Africa) |
| last_indexed | 2026-06-10T12:37:53.400Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2013 |
| publishDateRange | 2013 |
| publishDateSort | 2013 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/24337 Proteases and protease inhibitors involved in plant stress response and acclimation Kunert, Karl J. Foyer, Christine H. anneke.prins@hotmail.co.uk Prins, Anneke Rubisco Co2 enrichment Plant stress response Acclimation UCTD Thesis (PhD)--University of Pretoria, 2009. Proteases play a crucial role in plant defence mechanisms as well as acclimation to changing metabolic demands and environmental cues. Proteases regulate the development of a plant from germination through to senescence and plant death. In this thesis the role of proteases and their inhibitors in plant response to cold stress and CO2 enrichment were investigated. The activity and inhibition of cysteine proteases (CP), as well as degradation of their potential target proteins was investigated in transgenic tobacco plants expressing the rice cystatin, OC-I. Expression of OC-I caused a longer life span; delayed senescence; significant decrease in in vitro CP activity; a concurrent increase in protein content; and protection from chilling-induced decreases in photosynthesis. An initial proteomics study identified altered abundance of a cyclophilin, a histone, a peptidyl-prolyl cis-trans isomerase and two RuBisCO activase isoforms in OC-I expressing leaves. Immunogold labelling studies revealed that RuBisCO and OC-I is present in RuBisCO vesicular bodies (RVB) that appear to be important in RuBisCO degradation in leaves under optimal and stress conditions. Plants need to respond quickly to changes in the environment that cause changes in the demand for photosynthesis. In this study the effect of CO2 enrichment on photosynthesis-related genes and novel proteases and protease inhibitors regulated by CO2 enrichment and/or development, was investigated. Maize plants grown to maturity with CO2 enrichment showed significant changes in leaf chlorophyll and protein content, increased epidermal cell size, and decreased epidermal cell density. An increased stomatal index in leaves grown at high-CO2 indicates that leaves adjust their stomatal densities through changes in epidermal cell numbers rather than stomatal numbers. Photosynthesis and carbohydrate metabolism were not significantly affected. Developmental stage affected over 3000 transcripts between leaf ranks 3 and 12, while 142 and 90 transcripts were modified by high CO2 in the same leaf ranks respectively. Only 18 transcripts were affected by CO2 enrichment exclusively. Particularly, two novel CO2 -modulated serine protease inhibitors modulated by both sugars and pro-oxidants, were identified. Growth with high CO2 decreased oxidative damage to leaf proteins. Plant Science unrestricted 2013-09-06T17:16:14Z 2009-04-07 2013-09-06T17:16:14Z 2008-09-03 2009-04-07 2009-01-21 Thesis a 2008 D557/ag http://hdl.handle.net/2263/24337 http://upetd.up.ac.za/thesis/available/etd-01212009-093119/ © University of Pretoria 2008 D557/ application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf University of Pretoria |
| spellingShingle | Rubisco Co2 enrichment Plant stress response Acclimation UCTD Proteases and protease inhibitors involved in plant stress response and acclimation |
| title | Proteases and protease inhibitors involved in plant stress response and acclimation |
| title_full | Proteases and protease inhibitors involved in plant stress response and acclimation |
| title_fullStr | Proteases and protease inhibitors involved in plant stress response and acclimation |
| title_full_unstemmed | Proteases and protease inhibitors involved in plant stress response and acclimation |
| title_short | Proteases and protease inhibitors involved in plant stress response and acclimation |
| title_sort | proteases and protease inhibitors involved in plant stress response and acclimation |
| topic | Rubisco Co2 enrichment Plant stress response Acclimation UCTD |
| url | http://hdl.handle.net/2263/24337 http://upetd.up.ac.za/thesis/available/etd-01212009-093119/ |