The evolution of the plant organellar proteome
<p>A hallmark of eukaryotic cells is the compartmentalisation of intracellular processes into specialised, membrane-bound compartments known as organelles. The function of organelles is dependent on a suite of proteins localised within them (the organellar proteome), the majority of which are...
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| Format: | Thesis |
| Language: | English |
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2021
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| _version_ | 1797108335067004928 |
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| author | Costello, RMO |
| author2 | Kelly, S |
| author_facet | Kelly, S Costello, RMO |
| author_sort | Costello, RMO |
| collection | OXFORD |
| description | <p>A hallmark of eukaryotic cells is the compartmentalisation of intracellular processes into specialised, membrane-bound compartments known as organelles. The function of organelles is dependent on a suite of proteins localised within them (the organellar proteome), the majority of which are encoded in the nucleus and targeted to the correct organelle from the cytosol. Divergent evolution of organelles in different eukaryotic lineages is thus expected to arise, in part, due to differences in the set of nuclear-encoded proteins targeted to them. However, neither the rate at which differences in protein targeting accumulate, nor the evolutionary consequences of these changes, are known. The research presented in this thesis aims to address this gap in our knowledge through the development of a phylogenomic approach to identify the changes in organellar protein targeting that have occurred during the evolution of a diverse set of land plant species. It is revealed that there has been considerable, and continual, modulation of organellar proteomes during plant evolution. The rate of change in protein targeting is assessed, and a previously hidden link between gene duplication and the rate of organellar proteome evolution is uncovered. Next, the focus is narrowed, and the changes in organellar protein targeting that occurred during the evolution of a particular plant trait – C4 photosynthesis – in two independent C4 grass lineages are investigated. Of particular interest here is the identification of a novel beta-glucosidase enzyme that was relocated to the chloroplast during C4 evolution, and that may function to activate chloroplast development in the bundle sheath cells; a key feature of C4 leaves. This analysis also highlights a gap in our understanding of the C4 biochemical pathway in the crop plant maize. Specifically, it is unknown how the C4 metabolite aspartate is processed in the bundle sheath cells and thus an attempt is made to identify and experimentally characterise a novel enzyme that might catalyse this missing reaction. Together, the chapters of this thesis explore the mechanisms by which molecular sequence evolution leads to changes in protein function through changes in protein localisation and the consequences thereof at a macro- (e.g., organellar evolution) and micro- (e.g., subcellular pathways in a single species) level.</p> |
| first_indexed | 2024-03-07T07:26:02Z |
| format | Thesis |
| id | oxford-uuid:ac9db73c-a688-4576-a724-048b5e0339f6 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T07:26:02Z |
| publishDate | 2021 |
| record_format | dspace |
| spelling | oxford-uuid:ac9db73c-a688-4576-a724-048b5e0339f62022-11-18T16:03:15ZThe evolution of the plant organellar proteomeThesishttp://purl.org/coar/resource_type/c_db06uuid:ac9db73c-a688-4576-a724-048b5e0339f6PhotosynthesisProtein targetingProteomeGene duplicationPlant organellesC4 photosynthesisPlant diversityEvolutionEnglishHyrax Deposit2021Costello, RMOKelly, S<p>A hallmark of eukaryotic cells is the compartmentalisation of intracellular processes into specialised, membrane-bound compartments known as organelles. The function of organelles is dependent on a suite of proteins localised within them (the organellar proteome), the majority of which are encoded in the nucleus and targeted to the correct organelle from the cytosol. Divergent evolution of organelles in different eukaryotic lineages is thus expected to arise, in part, due to differences in the set of nuclear-encoded proteins targeted to them. However, neither the rate at which differences in protein targeting accumulate, nor the evolutionary consequences of these changes, are known. The research presented in this thesis aims to address this gap in our knowledge through the development of a phylogenomic approach to identify the changes in organellar protein targeting that have occurred during the evolution of a diverse set of land plant species. It is revealed that there has been considerable, and continual, modulation of organellar proteomes during plant evolution. The rate of change in protein targeting is assessed, and a previously hidden link between gene duplication and the rate of organellar proteome evolution is uncovered. Next, the focus is narrowed, and the changes in organellar protein targeting that occurred during the evolution of a particular plant trait – C4 photosynthesis – in two independent C4 grass lineages are investigated. Of particular interest here is the identification of a novel beta-glucosidase enzyme that was relocated to the chloroplast during C4 evolution, and that may function to activate chloroplast development in the bundle sheath cells; a key feature of C4 leaves. This analysis also highlights a gap in our understanding of the C4 biochemical pathway in the crop plant maize. Specifically, it is unknown how the C4 metabolite aspartate is processed in the bundle sheath cells and thus an attempt is made to identify and experimentally characterise a novel enzyme that might catalyse this missing reaction. Together, the chapters of this thesis explore the mechanisms by which molecular sequence evolution leads to changes in protein function through changes in protein localisation and the consequences thereof at a macro- (e.g., organellar evolution) and micro- (e.g., subcellular pathways in a single species) level.</p> |
| spellingShingle | Photosynthesis Protein targeting Proteome Gene duplication Plant organelles C4 photosynthesis Plant diversity Evolution Costello, RMO The evolution of the plant organellar proteome |
| title | The evolution of the plant organellar proteome |
| title_full | The evolution of the plant organellar proteome |
| title_fullStr | The evolution of the plant organellar proteome |
| title_full_unstemmed | The evolution of the plant organellar proteome |
| title_short | The evolution of the plant organellar proteome |
| title_sort | evolution of the plant organellar proteome |
| topic | Photosynthesis Protein targeting Proteome Gene duplication Plant organelles C4 photosynthesis Plant diversity Evolution |
| work_keys_str_mv | AT costellormo theevolutionoftheplantorganellarproteome AT costellormo evolutionoftheplantorganellarproteome |