• Hypoxia
• Re-oxygenation
• RNA interference
• Arabidopsis thaliana

Plants often experience low oxygen conditions as a consequence of flooding or waterlogging. Oxygen deficiency leads to a drastic reduction in mitochondrial respiration and subsequently in energy production. To cope with this situation, plants activate a series of physiological, biochemical and morphological responses to survive. Among these responses, the shift from aerobic metabolism to anaerobic fermentation represents the main mechanism to enable energy production, albeit with significantly lower yield.
Once the stress condition has been overcome, plants need to respond quickly in terminating the hypoxic response to restore aerobic metabolism for several reasons. First, aerobic metabolism is more efficient in generating energy compared to anaerobic fermentation. Second, if the hypoxic response continues even after oxygen is available again, the accumulation of toxic metabolites, such as ethanol and lactic acid, as well as reactive oxygen species, can occur. These toxic by-products can cause cellular damages.
The aim of this thesis is to evaluate the time required to terminate the hypoxic response upon reoxygenation and to investigate the potential involvement of the RNA interference (RNAi) in this inactivation process. Additionally, the study aims to assess whether the contribution of atmospheric oxygen is sufficient for the inactivation of the hypoxic response or if photosynthetic oxygen is also necessary. The model organism Arabidopsis thaliana has been chosen for addressing the proposed objectives.