Photorespiration protects C3 plants from photooxidation

Kozaki, Akiko; Takeba, Go

doi:10.1038/384557a0

Cited by 535 publications

(417 citation statements)

References 22 publications

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“…GS1 protein concentration increase during leaf senescence, while the concentration of GS2 decline in parallel with the decrease of chlorophyll, Rubisco, and soluble proteins (Kawakami and Watanabe 13 1988, Kamachi et al 1991). These patterns illustrate the roles of GS1 in the synthesis of translocatable nitrogenous compounds (glutamine) in the senescent leaf, and of GS2 in capturing ammonium molecules which are released during photorespiration (Kozaki and Takeba 1996). Though mRNA levels do not necessarily correspond to the levels of the corresponding proteins, the similarity of the time-courses of relative mRNA levels of Rubisco and GS2 indicates the involvement of GS2 in photosynthesis-related processes (Fig.…”

Section: Discussionmentioning

confidence: 96%

Developmental regulation of photosynthate distribution in leaves of rice

Shinano

Nakajima²,

Wasaki

et al. 2006

Photosynt.

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AbstractmRNA expression patterns of genes for metabolic key-enzymes (sucrose phosphate synthase [SPS], phosphoenolpyruvate carboxylase [PEPC], pyruvate kinase, ribulose 1,5-bisphosphate carboxylase/oxygenase, glutamine synthetase 1, and glutamine synthetase 2) were investigated in leaves of rice plants grown at two nitrogen (N) concentrations. The relative gene expression patterns were similar in all leaves except for 9 th leaf, in which mRNA levels were generally depressed.Though an increased N concentrations prolonged the expression period of each mRNA, it did not affect the relative expression intensity of any mRNA in a given leaf. SPS V max , SPS limiting activity, PEPC activity, and carbon flow were examined using 14 CO 2 . The ratio between PEPC activity and SPS V max was higher in leaves developed at the vegetative growth stage (vegetative leaves: 5 th and 7 th 1 leaf) than in leaves developed after the ear primordia formation stage (reproductive leaves: 9 th and flag leaf). PEPC activity and SPS V max decreased with declining leaf N concentration. The 14 C photosynthate distribution to the amino acids fraction was higher in vegetative than in reproductive leaves when compared for the same leaf N status. Thus, at high PEPC activity to SPS activity ratio, more 14 C photosynthate was distributed to the amino acid pool, whereas at higher SPS activity, more 14 C was channeled into the carbohydrate fraction. Thus, leaf ontogeny was an important factor controlling photosynthate distribution to the Nor C-pool, respectively, regardless of leaf N status.

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Section: Discussionmentioning

confidence: 96%

Developmental regulation of photosynthate distribution in leaves of rice

Shinano

Nakajima²,

Wasaki

et al. 2006

Photosynt.

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“…eral plants (Desikan et al, 1998;Delledonne et al, 2001;Krause and Durner, 2004). Energy dissipation mechanisms such as photorespiration or the water-water cycle (Asada, 2006) prevent excessive photoreduction of oxygen, which could potentially generate an excess of ROS, leading to photooxidation (Kozaki and Takeba, 1996;Osmond et al, 1997). Thus, inhibition of GDC should result in enhanced ROS.…”

Section: Mitochondrial and Cellular Responses To Gdc Inhibitionmentioning

confidence: 99%

Regulation of Plant Glycine Decarboxylase byS-Nitrosylation and Glutathionylation

et al. 2010

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Mitochondria play an essential role in nitric oxide (NO) signal transduction in plants. Using the biotin-switch method in conjunction with nano-liquid chromatography and mass spectrometry, we identified 11 candidate proteins that were S-nitrosylated and/or glutathionylated in mitochondria of Arabidopsis (Arabidopsis thaliana) leaves. These included glycine decarboxylase complex (GDC), a key enzyme of the photorespiratory C 2 cycle in C3 plants. GDC activity was inhibited by S-nitrosoglutathione due to S-nitrosylation/S-glutathionylation of several cysteine residues. Gas-exchange measurements demonstrated that the bacterial elicitor harpin, a strong inducer of reactive oxygen species and NO, inhibits GDC activity. Furthermore, an inhibitor of GDC, aminoacetonitrile, was able to mimic mitochondrial depolarization, hydrogen peroxide production, and cell death in response to stress or harpin treatment of cultured Arabidopsis cells. These findings indicate that the mitochondrial photorespiratory system is involved in the regulation of NO signal transduction in Arabidopsis.

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“…The sensitivity of a ndhB Ϫ mutant to photo-inhibition was explained by an involvement of the NDH complex in the control of electron flow through PSII, which may be mediated by pH changes. Noticeably, photorespiration has been proposed to protect C 3 plants from photooxidation and to prevent photo-inhibition (Heber et al, 1995b;Kozaki and Takeba, 1996). Therefore, a possible role of the NDH complex in producing extra-ATP necessary to sustain high photorespiration rates should also be considered to explain the higher sensitivity of ndhB Ϫ to photo-inhibition.…”

Section: Atp Supply Cyclic Electron Flow and Photorespirationmentioning

confidence: 99%

Increased Sensitivity of Photosynthesis to Antimycin A Induced by Inactivation of the Chloroplast ndhB Gene. Evidence for a Participation of the NADH-Dehydrogenase Complex to Cyclic Electron Flow around Photosystem I

et al. 2001

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) were used to study the role of the NADH-dehydrogenase complex (NDH) during photosynthesis and particularly the involvement of this complex in cyclic electron flow around photosystem I (PSI). Photosynthetic activity was determined on leaf discs by measuring CO 2 exchange and chlorophyll fluorescence quenchings during a dark-to-light transition. In the absence of treatment, both non-photochemical and photochemical fluorescence quenchings were similar in ndhB Ϫ and wild type (WT). When leaf discs were treated with 5 m antimycin A, an inhibitor of cyclic electron flow around PSI, both quenchings were strongly affected. At steady state, maximum photosynthetic electron transport activity was inhibited by 20% in WT and by 50% in ndhB Ϫ . Under non-photorespiratory conditions (2% O 2 , 2,500 L L Ϫ1 CO 2 ), antimycin A had no effect on photosynthetic activity of WT, whereas a 30% inhibition was observed both on quantum yield of photosynthesis assayed by chlorophyll fluorescence and on CO 2 assimilation in ndhB Ϫ . The effect of antimycin A on ndhB Ϫ could not be mimicked by myxothiazol, an inhibitor of the mitochondrial cytochrome bc 1 complex, therefore showing that it is not related to an inhibition of the mitochondrial electron transport chain but rather to an inhibition of cyclic electron flow around PSI. We conclude to the existence of two different pathways of cyclic electron flow operating around PSI in higher plant chloroplasts. One of these pathways, sensitive to antimycin A, probably involves ferredoxin plastoquinone reductase, whereas the other involves the NDH complex. The absence of visible phenotype in ndhB Ϫ plants under normal conditions is explained by the complement of these two pathways in the supply of extra-ATP for photosynthesis.During oxygenic photosynthesis of C 3 plants, both photosystem II (PSII) and photosystem I (PSI) cooperate to achieve NADP ϩ reduction using water as an electron donor and generate a trans-membrane proton gradient driving ATP synthesis. Although NADP ϩ reduction is recognized to be dependent on the activity of both photosystems through electron transport reactions of the "Z" scheme (Hill and Bendall, 1960;Redding et al., 1999), it has early been reported from studies on isolated thylakoids that ATP could be produced by the sole PSI through cyclic electron transfer reactions (Arnon, 1959). The cyclic electron flow around PSI has been extensively studied in thylakoids and/or chloroplasts of C 3 plants (for review, see Fork and Herbert, 1993; Bendall and Manasse, 1995). This mechanism has been suggested to provide ATP for a variety of cellular processes, including stress adaptation (Havaux et al., 1991) and CO 2 fixation (Furbank and Horton, 1987; Herbert et al., 1990). During photosynthetic CO 2 fixation, both NADPH and ATP are used to regenerate ribulose-1,5-bisphosphate and allow functioning of the photosynthetic carbon reduction cycle (Calvin cycle). In the absence of Q cycle, when one NADPH is produced by linear electron transport reactions, four H ϩ are released in ...

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Photorespiration protects C3 plants from photooxidation

Cited by 535 publications

References 22 publications

Developmental regulation of photosynthate distribution in leaves of rice

Developmental regulation of photosynthate distribution in leaves of rice

Regulation of Plant Glycine Decarboxylase byS-Nitrosylation and Glutathionylation

Increased Sensitivity of Photosynthesis to Antimycin A Induced by Inactivation of the Chloroplast ndhB Gene. Evidence for a Participation of the NADH-Dehydrogenase Complex to Cyclic Electron Flow around Photosystem I

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