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%0 Thesis
%A Jordine, Angelina Maria Katharina
%T Unraveling the resilience of Salicornia europaea : physiological and molecular responses to combined environmental stresses
%I RWTH Aachen University
%V Dissertation
%C Aachen
%M RWTH-2025-11026
%P 1 Online-Ressource : Illustrationen
%D 2025
%Z Veröffentlicht auf dem Publikationsserver der RWTH Aachen University 2026
%Z Dissertation, RWTH Aachen University, 2025
%X Plants are sessile organisms that must cope with fluctuating and often extreme environ- mental conditions through adaptive physiological and molecular mechanisms. Climate change is increasing the frequency of abiotic stress events, such as flooding (hypoxia) and salinity, which often occur simultaneously in natural habitats. Understanding how plants respond to combinations of stressors is crucial for unraveling the mechanisms underlying stress tolerance. Most previous studies have focused on stress-sensitive model plants like Arabidopsis thaliana, which mainly reveal damage responses, whereas naturally adapted halophytes offer insights into survival strategies. Salicornia europaea, a succulent halophyte of European salt marshes, exhibits high tolerance to salinity and periodic flooding. In this study, I used S. europaea to investigate the physiological, molecular, and transcriptional responses to salt, hypoxia, and simultaneous hypoxia-salt stress, to establish it as a model for simultaneous stress studies. Plants exposed to high salt concentrations (up to 2.5 M) or prolonged submergence (6 weeks) confirmed the high resilience of S. europaea under these stresses. Additionally, quantitative polymerase chain reaction (PCR) analysis revealed that hypoxia-responsive genes were induced under low oxygen conditions, but not during natural tidal flooding, suggesting efficient adaptation. Sequential exposure to salt and hypoxia altered the expression of several hypoxia-responsive genes, indicating potential crosstalk between stress response path- ways and highlighting the suitability of S. europaea as a model system for studying adaptive mechanisms under combined stresses. To investigate regulatory mechanisms, I focused on the group VII ethylene-responsive transcription factors (ERFVIIs), which are substrates of the oxygen-dependent PRT6-mediated N-degron pathway integrating salinity and hypoxia responses in A. thaliana. I assessed the involvement of ERFVIIs under simultaneous stress by exposing Arabidopsis thaliana mutants to salt and anoxia treatments. ERFVII-deficient mutants displayed better survival compared to plants lacking only HREs (Hypoxia responsive ERFVII), suggesting a specific role in adaptation. Gene expression analysis via RT-qPCR revealed differential regulation of RAPs (Related to APETALA2) and HREs under simultaneous hypoxia-salt treatment. In comparison, S. europaea displayed stronger activation of ERFVIIs as well as hypoxia- and salt-related genes, pointing to species-specific regulatory strategies. Finally, transcriptome-wide analysis using RNA sequencing revealed that combined hypoxia-salt stress induces complex transcriptional reprogramming in S. europaea. Compared to single stresses, simultaneous stress triggered about 10
%F PUB:(DE-HGF)11
%9 Dissertation / PhD Thesis
%R 10.18154/RWTH-2025-11026
%U https://publications.rwth-aachen.de/record/1024166