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Light-Dark and Thioredoxin-Mediated Metabolic Redox Control in Plant Cells

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The Redox State and Circadian Rhythms

Abstract

Plants require mechanisms to sense the diurnal light-dark rhythms in order to activate and deactivate enzyme activities in the chloroplast and avoid futile cycles of assimilate formation and degradation. In a redox signal chain, light perceived at the photosystems generates reduced ferredoxin, ferredoxin:thioredoxin reductase, and two reduced thioredoxins f and m which in turn reduce regulatory disulfide bridges in a number of target enzymes. Thus, the redox potential of the chloroplast thioredoxin system (but not the total amount of its components) fluctuate during the day. Redox regulation by thiol-disulfide changes is known to affect (at least) 15 different plant enzymes which control carbon dioxide, nitrogen, and sulfate assimilation, energy production, lipid and chlorophyll biosynthesis. Leaves and green algae exhibit certain differences in their thioredoxin and thioredoxin target patterns. The light-responsive thioredoxin system can in fact be viewed as main coordinating factor of plastid metabolism. At the same time, however, the exposed disulfide bond of oxidized thioredoxin makes the system susceptible to chemical damage and has been identified as a primary cause of sulfur dioxide phytotoxicity.

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Thérèse Vanden Driessche Jean-Luc Guisset Ghislaine M. Petiau-de Vries

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Follmann, H. (2000). Light-Dark and Thioredoxin-Mediated Metabolic Redox Control in Plant Cells. In: Driessche, T.V., Guisset, JL., Petiau-de Vries, G.M. (eds) The Redox State and Circadian Rhythms. Springer, Dordrecht. https://doi.org/10.1007/978-94-015-9556-8_4

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