Photorespiratory 2-phosphoglycolate metabolism and photoreduction of O2 cooperate in high-light acclimation of Synechocystis sp. strain PCC 6803
Autor: | Floyd R.A. Wittink, Hermann Bauwe, Martin Hagemann, Aaron Kaplan, Hans C. P. Matthijs, Annerose Engelhardt, Claudia Hackenberg |
---|---|
Přispěvatelé: | RNA Biology & Applied Bioinformatics (SILS, FNWI), Aquatic Microbiology (IBED, FNWI) |
Rok vydání: | 2009 |
Předmět: |
Cyanobacteria
Chlorophyll Photoinhibition Genotype Light Acclimatization Mutant Immunoblotting Mehler reaction Glycine decarboxylase complex Plant Science Photosynthesis Fluorescence Genetics Chlorophyll fluorescence Oligonucleotide Array Sequence Analysis biology Synechocystis DNA microarray Photosystem II Protein Complex Gene Expression Regulation Bacterial Carbon Dioxide biology.organism_classification Aerobiosis Glycolates Oxygen Biochemistry Genes Bacterial Mutation Photorespiration Original Article Oxidation-Reduction |
Zdroj: | Planta, 230(4), 625-637. Springer Verlag Planta |
ISSN: | 1432-2048 0032-0935 |
Popis: | In cyanobacteria, photorespiratory 2-phosphoglycolate (2PG) metabolism is mediated by three different routes, including one route involving the glycine decarboxylase complex (Gcv). It has been suggested that, in addition to conversion of 2PG into non-toxic intermediates, this pathway is important for acclimation to high-light. The photoreduction of O2 (Mehler reaction), which is mediated by two flavoproteins Flv1 and Flv3 in cyanobacteria, dissipates excess reductants under high-light by the four electron-reduction of oxygen to water. Single and double mutants defective in these processes were constructed to investigate the relation between photorespiratory 2PG-metabolism and the photoreduction of O2 in the cyanobacterium Synechocystis sp. PCC 6803. The single mutants Δflv1, Δflv3, and ΔgcvT, as well as the double mutant Δflv1/ΔgcvT, were completely segregated but not the double mutant Δflv3/ΔgcvT, suggesting that the T-protein subunit of the Gcv (GcvT) and Flv3 proteins cooperate in an essential process. This assumption is supported by the following results: (1) The mutant Δflv3/ΔgcvT showed a considerable longer lag phase and sometimes bleached after shifts from slow (low light, air CO2) to rapid (standard light, 5% CO2) growing conditions. (2) Photoinhibition experiments indicated a decreased ability of the mutant Δflv3/ΔgcvT to cope with high-light. (3) Fluorescence measurements showed that the photosynthetic electron chain is reduced in this mutant. Our data suggest that the photorespiratory 2PG-metabolism and the photoreduction of O2, particularly that catalyzed by Flv3, cooperate during acclimation to high-light stress in cyanobacteria. Electronic supplementary material The online version of this article (doi:10.1007/s00425-009-0972-9) contains supplementary material, which is available to authorized users. |
Databáze: | OpenAIRE |
Externí odkaz: |