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Regulation of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) in response to the exposure of moderate irradiance-grown Arabidopsis thaliana plants to low irradiance

Magda Grabsztunowicz

Abstract

Rubisco is a bifunctional enzyme that catalyzes two competing reactions, namely photosynthetic CO2 assimilation and photorespiratory carbon oxidation. In terrestrial plants Rubisco exists as a holoenzyme composed of eight large (LS) and eight small subunits (SS). Rubisco is highly regulated in response to fluctuations in the environment both by the changes in amount and enzymatic activity. However, no complex data are available on Rubisco regulatory mechanisms triggered in plants which are submitted to moderate–low irradiance shift. In present study, moderate irradiance-grown A. thaliana plants were exposed to low irradiance conditions. The moderate– low irradiance shift for a single photoperiod caused the exclusion of a certain pool of Rubisco under altered conditions owing to oxidative modifications resulting in the formation of protein aggregates involving Rubisco-LS. As a result, Rubisco carboxylase activity was reduced. The results of the determination of reactive oxygen species indicated that a moderate-low irradiance transition had stimulated 1O2 accumulation, and probably the Rubisco oxidative modifications leading to formation of aggregates encompassing Rubisco-LS were triggered by 1O2. When moderate irradiance regime was resumed, the majority of Rubisco-LS containing aggregates tended to be resolubilized, and this allowed Rubisco carboxylation activities to be largely recovered.
Record ID
UAM7dd415e795584ad8a5ce671c22367afe
Diploma type
Doctor of Philosophy
Author
Title in Polish
Regulacja karboksylazy/oksygenazy rybulozo-1,5-bisfosforanu (Rubisco) u Arabidopsis thaliana w odpowiedzi na zmianę natężenia z umiarkowanego na niskie
Title in English
Regulation of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) in response to the exposure of moderate irradiance-grown Arabidopsis thaliana plants to low irradiance
Language
pol (pl) Polish
Certifying Unit
Faculty of Biology (SNP/WB/FoB)
Discipline
biology / (biological sciences domain) / (biological sciences)
Scientific discipline (2.0)
6.4 biological sciences
Status
Finished
Defense Date
28-05-2015
Title date
28-05-2015
Supervisor
URL
http://hdl.handle.net/10593/13075 Opening in a new tab
Keywords in English
low irradiance, reactive oxygen species, chloroplasts
Abstract in English
Rubisco is a bifunctional enzyme that catalyzes two competing reactions, namely photosynthetic CO2 assimilation and photorespiratory carbon oxidation. In terrestrial plants Rubisco exists as a holoenzyme composed of eight large (LS) and eight small subunits (SS). Rubisco is highly regulated in response to fluctuations in the environment both by the changes in amount and enzymatic activity. However, no complex data are available on Rubisco regulatory mechanisms triggered in plants which are submitted to moderate–low irradiance shift. In present study, moderate irradiance-grown A. thaliana plants were exposed to low irradiance conditions. The moderate– low irradiance shift for a single photoperiod caused the exclusion of a certain pool of Rubisco under altered conditions owing to oxidative modifications resulting in the formation of protein aggregates involving Rubisco-LS. As a result, Rubisco carboxylase activity was reduced. The results of the determination of reactive oxygen species indicated that a moderate-low irradiance transition had stimulated 1O2 accumulation, and probably the Rubisco oxidative modifications leading to formation of aggregates encompassing Rubisco-LS were triggered by 1O2. When moderate irradiance regime was resumed, the majority of Rubisco-LS containing aggregates tended to be resolubilized, and this allowed Rubisco carboxylation activities to be largely recovered.

Uniform Resource Identifier
https://researchportal.amu.edu.pl/info/phd/UAM7dd415e795584ad8a5ce671c22367afe/
URN
urn:amu-prod:UAM7dd415e795584ad8a5ce671c22367afe

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