Dokument: Functional characterization of peroxisomal transport protein in Arabidopsis thaliana – role in stress adaptation and redox homeostasis
| Titel: | Functional characterization of peroxisomal transport protein in Arabidopsis thaliana – role in stress adaptation and redox homeostasis | |||||||
| URL für Lesezeichen: | https://docserv.uni-duesseldorf.de/servlets/DocumentServlet?id=71952 | |||||||
| URN (NBN): | urn:nbn:de:hbz:061-20260120-123035-9 | |||||||
| Kollektion: | Dissertationen | |||||||
| Sprache: | Englisch | |||||||
| Dokumententyp: | Wissenschaftliche Abschlussarbeiten » Dissertation | |||||||
| Medientyp: | Text | |||||||
| Autor: | Krawczyk, Katarzyna Janina [Autor] | |||||||
| Dateien: |
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| Beitragende: | Prof. Dr. Linka, Nicole [Gutachter] Prof. Dr. Weber, Andreas [Gutachter] | |||||||
| Dewey Dezimal-Klassifikation: | 500 Naturwissenschaften und Mathematik » 580 Pflanzen (Botanik) | |||||||
| Beschreibung: | Summary
Plant peroxisomes play a central role in metabolism, cellular redox homeostasis, and stress adaptation. Many antioxidative processes occur in peroxisomes, thus understanding their function is crucial for mitigating the negative effects of environmental stress and preventing loss of crop yield. While many peroxisomal enzymes have been already characterized, only a few membrane transporters are known, limiting our understanding how plans regulate metabolite exchange during stress. Therefore, this thesis focuses on PERTL6 (peroxisomal-transport like protein 6) in Arabidopsis thaliana. PERTL6 belongs to the mitochondrial carrier family and was found to be upregulated upon heat stress. Given the role of peroxisomes in antioxidative defense and the gap in knowledge regarding peroxisomal transporter facilitating antioxidants, the aim of this thesis was to determine the role PERTL6 in plant physiology, with a particular emphasis on oxidative stress response. An integrative approach was employed to fully portray the role of PERTL6. Subcellular localization was determined by using fusion with fluorescent proteins, revealing that contrastingly with previous predictions, PERTL6 is indeed localized to peroxisomal membrane. Phylogenetic studies identified PERTL6 as land-specific protein encoded by a single gene in Arabidopsis thaliana. In silico promoter region analysis revealed multiple cis elements related to stress, which was consistent with co-expression network data linking PERTL6 to genes encoded heat shock proteins or proteins involved in proteolysis. Physiological experiments were conducted utilizing several pertl6 lines, including established CRISPR/Cas9-generated knockouts. Physiological assays included growth assessments, photosynthetic efficiency (Fv/Fm) measurements, CO2 assimilation, germination assays or transcript quantification under various oxidative stress-inducing conditions such as heat shock, prolonged warming, salt stress, photorespiratory stress and extended darkness. Metabolites profiling was used to identify shifts in metabolites induced by stress. Although pertl6 mutants did not show severe growth defects, they displayed altered metabolic responses. Notably, mutants accumulated higher levels of ornithine and arginine and showed disruption in TCA cycle intermediates, supporting the hypothesis PERTL6 exacerbates redox imbalance and metabolic flexibility. The accumulation of arginine, ornithine, points to a potential role in amino acid transport, potentially linking the urea cycle, polyamine biosynthesis and central carbon metabolism. In conclusion, this work provides the first functional characterization of PERTL6, identifying it as a candidate for peroxisomal ornithine/arginine transporter. The results suggest that PERTL6 supports the peroxisomal antioxidative machinery and plays a role in nitrogen metabolism, particularly under stress conditions. These findings contribute to a broader understanding of how peroxisomes integrate into plant metabolic networks and allocate resources during stress adaptation. | |||||||
| Lizenz: |  Dieses Werk ist lizenziert unter einer Creative Commons Namensnennung 4.0 International Lizenz | |||||||
| Fachbereich / Einrichtung: | Mathematisch- Naturwissenschaftliche Fakultät » WE Biologie » Biochemie der Pflanzen | |||||||
| Dokument erstellt am: | 20.01.2026 | |||||||
| Dateien geändert am: | 20.01.2026 | |||||||
| Promotionsantrag am: | 01.06.2021 | |||||||
| Datum der Promotion: | 19.01.2026 |
