Changes in light energy distribution upon state transitions: an in vivo photoacoustic study of the wild type and photosynthesis mutants from Chlamydomonas reinhardtii

Delosme, René; Olive, Jacqueline; Wollman, Françis-André

doi:10.1016/0005-2728(95)00143-3

Cited by 199 publications

(143 citation statements)

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“…Previous studies have shown that in C. reinhardtii, a shift to state 2 corresponds to the displacement of 80% of the LHCII from PSII to PSI, leading to an increase of PSI antenna size of 50% in red light compared with state 1 (Delosme et al, 1996). This increase, together with the 50% stimulation of ES in the most affected mutants, would lead to more than doubling the rate of cyclic electron flow under constant excitation conditions.…”

Section: Discussionmentioning

confidence: 92%

Photosynthesis and State Transitions in Mitochondrial Mutants ofChlamydomonas reinhardtiiAffected in Respiration

et al. 2003

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Photosynthetic activities were analyzed in Chlamydomonas reinhardtii mitochondrial mutants affected in different complexes (I, III, IV, I ϩ III, and I ϩ IV) of the respiratory chain. Oxygen evolution curves showed a positive relationship between the apparent yield of photosynthetic linear electron transport and the number of active proton-pumping sites in mitochondria. Although no significant alterations of the quantitative relationships between major photosynthetic complexes were found in the mutants, 77 K fluorescence spectra showed a preferential excitation of photosystem I (PSI) compared with wild type, which was indicative of a shift toward state 2. This effect was correlated with high levels of phosphorylation of lightharvesting complex II polypeptides, indicating the preferential association of light-harvesting complex II with PSI. The transition to state 1 occurred in untreated wild-type cells exposed to PSI light or in 3-(3,4-dichlorophenyl)-1,1-dimethylureatreated cells exposed to white light. In mutants of the cytochrome pathway and in double mutants, this transition was only observed in white light in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea. This suggests higher rates of nonphotochemical plastoquinone reduction through the chlororespiratory pathway, which was confirmed by measurements of the complementary area above the fluorescence induction curve in dark-adapted cells. Photo-acoustic measurements of energy storage by PSI showed a stimulation of PSI-driven cyclic electron flow in the most affected mutants. The present results demonstrate that in C. reinhardtii mutants, permanent defects in the mitochondrial electron transport chain stabilize state 2, which favors cyclic over linear electron transport in the chloroplast.Metabolic processes of photosynthetic organisms depend on the regeneration of ATP through photosynthesis and respiration. Although these two processes are now well understood at the molecular and physiological levels, less is known about their mutual regulation. In eukaryotic cells, complex interactions between photosynthesis and respiration occur because both processes are linked by common key metabolites such as ADP/ATP, NAD(P)H, triose-P, and hexose-P (for review, see Hoefnagel et al., 1998).When the dependence of respiration on photosynthesis seems to rely essentially on the availability of substrates, the influence of respiration on photosynthesis is suggested to involve complex organizational changes in the PSs, known as state transitions. The transition from states 1 to 2 corresponds to the reversible transfer of a mobile pool of PSII lightharvesting complexes II (LHCII) from PSII to PSI along the thylakoid membrane (state 2 transition) and is triggered by persistent reduction of the plastoquinone (PQ) pool. This reduction causes the activation of an LHCII-kinase interacting with the quinine oxidizing site of cytochrome (Cyt) b6/f (for review, see Allen, 1992;Wollman, 2001). Due to its high affinity for the PSI-h subunit, phospho-LHCII then is bound preferential...

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Section: Discussionmentioning

confidence: 92%

Photosynthesis and State Transitions in Mitochondrial Mutants ofChlamydomonas reinhardtiiAffected in Respiration

et al. 2003

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“…In State I, the mobile part of LHCII is associated with PSII. Preferential excitation energy flux to PSII reduces the plastoquinone pool and leads to the activation of the LHCII kinase and phosphorylation of LHCII that is laterally displaced from PSII in the grana to PSI in the stroma lamellae of the thylakoid membranes (Vallon et al, 1991;Delosme et al, 1996). Such a State I to State II transition is associated with a significant fluorescence decrease in C. reinhardtii because as much as 80% of LHCII is displaced.…”

Section: Dynamics Of the Photosynthetic Apparatusmentioning

confidence: 99%

Assembly, Function, and Dynamics of the Photosynthetic Machinery in Chlamydomonas reinhardtii

Rochaix¹

2001

Plant Physiology

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“…10) migrates reversibly from PSII to PSI. In the green alga Chlamydomonas reinhardtii, on the contrary, a much larger fraction of the PSII antenna is transferred during State 1-State 2 transition (14), and a much larger decrease of PSII energy capture is accordingly observed (15). In addition, cytochrome b 6 f complexes accumulate in the unstacked lamellae in State 2 (16).…”

mentioning

confidence: 98%

Photoinhibition of Chlamydomonas reinhardtii in State 1 and State 2

Finazzi¹,

Barbagallo²,

Bergo

et al. 2001

Journal of Biological Chemistry

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The relationship between state transitions and photoinhibition has been studied in Chlamydomonas reinhardtii cells. In State 2, photosystem II activity was more inhibited by light than in State 1. In State 2, however, the D1 subunit was not degraded, whereas a substantial degradation was observed in State 1. These results suggest that photoinhibition occurs via the generation of an intermediate state in which photosystem II is inactive but the D1 protein is still intact. The accumulation of this state is enhanced in State 2, because in this State only cyclic photosynthetic electron transport is active, whereas there is no electron flow between photosystem II and the cytochrome b 6 f complex (Finazzi, G., Furia, A., Barbagallo, R. P., and Forti, G. (1999) Biochim. Biophys. Acta 1413, 117-129). The activity of photosystem I and of cytochrome b 6 f as well as the coupling of thylakoid membranes was not affected by illumination under the same conditions. This allows repairing the damages to photosystem II thanks to cell capacity to maintain a high rate of ATP synthesis (via photosystem I-driven cyclic electron flow). This capacity might represent an important physiological tool in protecting the photosynthetic apparatus from excess of light as well as from other a-biotic stress conditions. The photochemical utilization of absorbed light is a critical step in the photosynthetic process. Because harvesting of light, photochemistry, and electron transfer occur on widely different scales of time, a correct balance among these different processes is required to optimize the efficiency of CO 2 fixation.When light is absorbed in excess of what can actually be utilized by photochemistry, damage to the photosynthetic apparatus may be induced. Impairment of both photosystem I (PSI) 1 (1) and photosystem II (PSII) (2) has been described, and this loss of activity has been termed photoinhibition (3). It has been also shown that the degradation of the PSII reaction center D1 subunit is a major consequence of photoinhibition (2).Some mechanisms contribute to protecting the photosynthetic apparatus from an excess of light (4, 5). The first is the so-called energy-dependent quenching, qE, i.e. the increased thermal dissipation in the PSII antennae that follows the generation of the electrochemical proton gradient across the thylakoid membranes. It is supposed to protect the reaction center from the consequences of a strong illumination by reducing the amount of energy present in the antenna protein complexes (6).The second one (6) is state transitions, a phenomenon that has been discovered in Chlorella pyrenoidosa (7) and in Porphyridium cruentum (8). It is a mechanism to balance light utilization between the two photosystems that is based on the reversible transfer of a fraction of the light-harvesting complex II (LHCII) from PSII to PSI (reviewed in Refs 9 -11). It is also supposed to protect PSII from photoinhibition inasmuch as it can decrease the size of its antenna.The migration of LHCII to PSI (State 1-State 2 transition) re...

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Changes in light energy distribution upon state transitions: an in vivo photoacoustic study of the wild type and photosynthesis mutants from Chlamydomonas reinhardtii

Cited by 199 publications

References 32 publications

Photosynthesis and State Transitions in Mitochondrial Mutants ofChlamydomonas reinhardtiiAffected in Respiration

Photosynthesis and State Transitions in Mitochondrial Mutants ofChlamydomonas reinhardtiiAffected in Respiration

Assembly, Function, and Dynamics of the Photosynthetic Machinery in Chlamydomonas reinhardtii

Photoinhibition of Chlamydomonas reinhardtii in State 1 and State 2

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