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Investigating the role of phytohormones during desiccation in two evolutionarily distinct resurrection plants
Most plants encounter challenges brought on by various abiotic stressors which subsequently prompt adaptations to mitigate these challenges. Water deficit brought about by drought conditions is a significant abiotic stressor that impacts crop productivity, ultimately threatening global food security...
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| Format: | Thesis |
| Language: | English English |
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Department of Molecular and Cell Biology
2025
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| _version_ | 1867613819465891840 |
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| access_status_str | Open Access |
| author | Kirchner, Sabine Maye |
| author2 | Farrant, Jill Margaret |
| author_browse | Farrant, Jill Margaret Kirchner, Sabine Maye |
| author_facet | Farrant, Jill Margaret Kirchner, Sabine Maye |
| author_sort | Kirchner, Sabine Maye |
| collection | Thesis |
| description | Most plants encounter challenges brought on by various abiotic stressors which subsequently prompt adaptations to mitigate these challenges. Water deficit brought about by drought conditions is a significant abiotic stressor that impacts crop productivity, ultimately threatening global food security. Significant effort has thus gone into researching the unique adaptations that have allowed a remarkable group of angiosperms termed resurrection plants, to survive extreme water loss. This thesis focused on profiling phytohormone abundances in two evolutionarily distinct resurrection plant species; Craterostigma pumilum and Xerophyta schlechteri, during a dehydration time course. The objective was to elucidate some of the molecular processes that occur in the context of differing desiccation tolerance strategies, namely homoiochlorophylly and poikilochlorophylly. Hormone profiles were then followed up with gene expression analysis of desiccation-responsive genes RD29B and GASA3 in C. pumilum to further explore hormone signalling associated with jasmonates. In order to do this, and because the major findings on the roles of these genes in relation to jasomonate emanate from work on the model plant Arabidopsis thaliana, protocols designed for their analyses in that species were tested against C. pumilum to investigate their effectiveness when implemented in a non-model species. Species-specific hormone profiles were identified not only between the two resurrection plants, but also within their leaf and root tissues. ABA emerged as a central regulator of stress responses, while jasmonic acid (JA) appeared to play more of a supporting role, and the dynamics of OPDA, a precursor of JA, suggested a potential alternative signalling pathway that may occur in resurrection plants during desiccation. Overall, the findings point to species-specific hormone profiles that may be unique to resurrection plants and underscore the complexity of hormonal interactions in plant responses to water deficit stress. Additionally, results highlighted the need for further optimization of laboratory protocols designed with specific species in mind and warn against a potential over-reliance on protocols designed for model species. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/42339 |
| institution | University of Cape Town (South Africa) |
| language | English eng |
| last_indexed | 2026-06-10T12:42:12.590Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2025 |
| publishDateRange | 2025 |
| publishDateSort | 2025 |
| publisher | Department of Molecular and Cell Biology |
| publisherStr | Department of Molecular and Cell Biology |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/42339 Investigating the role of phytohormones during desiccation in two evolutionarily distinct resurrection plants Kirchner, Sabine Maye Farrant, Jill Margaret Vothknecht, Ute Van de Pas, Llewelyn Phytohormones Plants Most plants encounter challenges brought on by various abiotic stressors which subsequently prompt adaptations to mitigate these challenges. Water deficit brought about by drought conditions is a significant abiotic stressor that impacts crop productivity, ultimately threatening global food security. Significant effort has thus gone into researching the unique adaptations that have allowed a remarkable group of angiosperms termed resurrection plants, to survive extreme water loss. This thesis focused on profiling phytohormone abundances in two evolutionarily distinct resurrection plant species; Craterostigma pumilum and Xerophyta schlechteri, during a dehydration time course. The objective was to elucidate some of the molecular processes that occur in the context of differing desiccation tolerance strategies, namely homoiochlorophylly and poikilochlorophylly. Hormone profiles were then followed up with gene expression analysis of desiccation-responsive genes RD29B and GASA3 in C. pumilum to further explore hormone signalling associated with jasmonates. In order to do this, and because the major findings on the roles of these genes in relation to jasomonate emanate from work on the model plant Arabidopsis thaliana, protocols designed for their analyses in that species were tested against C. pumilum to investigate their effectiveness when implemented in a non-model species. Species-specific hormone profiles were identified not only between the two resurrection plants, but also within their leaf and root tissues. ABA emerged as a central regulator of stress responses, while jasmonic acid (JA) appeared to play more of a supporting role, and the dynamics of OPDA, a precursor of JA, suggested a potential alternative signalling pathway that may occur in resurrection plants during desiccation. Overall, the findings point to species-specific hormone profiles that may be unique to resurrection plants and underscore the complexity of hormonal interactions in plant responses to water deficit stress. Additionally, results highlighted the need for further optimization of laboratory protocols designed with specific species in mind and warn against a potential over-reliance on protocols designed for model species. 2025-11-26T07:40:04Z 2025-11-26T07:40:04Z 2025 2025-11-26T07:37:42Z Thesis / Dissertation Masters MSc http://hdl.handle.net/11427/42339 en eng application/pdf Department of Molecular and Cell Biology Faculty of Science University of Cape Town |
| spellingShingle | Phytohormones Plants Kirchner, Sabine Maye Investigating the role of phytohormones during desiccation in two evolutionarily distinct resurrection plants |
| thesis_degree_str | Master's |
| title | Investigating the role of phytohormones during desiccation in two evolutionarily distinct resurrection plants |
| title_full | Investigating the role of phytohormones during desiccation in two evolutionarily distinct resurrection plants |
| title_fullStr | Investigating the role of phytohormones during desiccation in two evolutionarily distinct resurrection plants |
| title_full_unstemmed | Investigating the role of phytohormones during desiccation in two evolutionarily distinct resurrection plants |
| title_short | Investigating the role of phytohormones during desiccation in two evolutionarily distinct resurrection plants |
| title_sort | investigating the role of phytohormones during desiccation in two evolutionarily distinct resurrection plants |
| topic | Phytohormones Plants |
| url | http://hdl.handle.net/11427/42339 |
| work_keys_str_mv | AT kirchnersabinemaye investigatingtheroleofphytohormonesduringdesiccationintwoevolutionarilydistinctresurrectionplants |