Circadian regulation of photosynthetic efficiency under fluctuating environmental conditions

Yiasoumi, Georgia (2022) Circadian regulation of photosynthetic efficiency under fluctuating environmental conditions. Masters thesis, University of East Anglia.

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In natural environments, plants experience constantly changing conditions. These environmental fluctuations lead to damage of the photosynthetic apparatus. This means that maintaining photosynthetic efficiency is underpinned by an ongoing cycle of damage and repair. This repair is supported by multiple layers of regulation – from rapidly induced response mechanisms to underlying circadian regulation – allowing appropriate responses to changes in condition intensity and duration be elicited. The SIGMA FACTOR 5 (SIG5) transcriptional pathway drives expression of genes in the chloroplast genome involved in photosynthesis. Previous studies have shown there is rapid induction of SIG5 expression in response to tissue exposure to multiple abiotic stress conditions. Further, in response to treatments of short-term cold and light conditions induction of SIG5 has been shown to be under circadian regulation. This thesis provides evidence that circadian regulation influences both the response and recovery of photosynthetic efficiency to short-term exposure to cold and high light conditions. In addition, this thesis shows this circadian regulation is in part mediated by the SIG5 transcriptional response pathway. Moreover, this regulation by the circadian oscillator and SIG5 varies with leaf developmental type, suggesting a differing vulnerability of leaf types to cold and high light conditions. Understanding how photosynthetic efficiency is regulated under different abiotic environmental conditions could be informative of how the photosynthetic fitness of ecosystems, both agricultural and natural, may be shaped by the changing climate.

Item Type: Thesis (Masters)
Faculty \ School: Faculty of Science > School of Biological Sciences
Depositing User: Chris White
Date Deposited: 23 Mar 2023 12:39
Last Modified: 23 Mar 2023 12:39

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