Photosystem II Excitation Pressure and Development of Resistance to Photoinhibition (I. Light-Harvesting Complex II Abundance and Zeaxanthin Content in Chlorella vulgaris)

Maxwell, Denis P.; Falk, Stefan; Hüner, Norman P. A.

doi:10.1104/pp.107.3.687

Cited by 185 publications

(136 citation statements)

References 21 publications

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“…A similar effect has been described in Chlorella vulgaris in response to high light treatment, which increases the excitation energy pressure on PSII (Maxwell et al, 1995). This also is consistent with the dwarf phenotype of ⌬ycf9 plants grown at low temperature, which closely parallels the effect of PSII overexcitation induced by moderate illumination at low temperature in barley (Huner et al, 1998).…”

Section: Discussionsupporting

confidence: 81%

The Chloroplast Gene ycf9 Encodes a Photosystem II (PSII) Core Subunit, PsbZ, That Participates in PSII Supramolecular Architecture

Świątek¹,

Kuras²,

Sokilenko³

et al. 2001

The Plant Cell

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We have characterized the biochemical nature and the function of PsbZ, the protein product of a ubiquitous open reading frame, which is known as ycf9 in Chlamydomonas and ORF 62 in tobacco, that is present in chloroplast and cyanobacterial genomes. After raising specific antibodies to PsbZ from Chlamydomonas and tobacco, we demonstrated that it is a bona fide photosystem II (PSII) subunit. PsbZ copurifies with PSII cores in Chlamydomonas as well as in tobacco. Accordingly, PSII mutants from Chlamydomonas and tobacco are deficient in PsbZ. Using psbZ -targeted gene inactivation in tobacco and Chlamydomonas, we show that this protein controls the interaction of PSII cores with the light-harvesting antenna; in particular, PSII-LHCII supercomplexes no longer could be isolated from PsbZ-deficient tobacco plants. The content of the minor chlorophyll binding protein CP26, and to a lesser extent that of CP29, also was altered substantially under most growth conditions in the tobacco mutant and in Chlamydomonas mutant cells grown under photoautotrophic conditions. These PsbZ-dependent changes in the supramolecular organization of the PSII cores with their peripheral antennas cause two distinct phenotypes in tobacco and are accompanied by considerable modifications in (1) the pattern of protein phosphorylation within PSII units, (2) the deepoxidation of xanthophylls, and (3) the kinetics and amplitude of nonphotochemical quenching. The role of PsbZ in excitation energy dissipation within PSII is discussed in light of its proximity to CP43, in agreement with the most recent structural data on PSII. INTRODUCTIONWith the completion of an ever-increasing number of chloroplast genome sequences (Quigley and Weil, 1985; Bookjans et al., 1986;Ohyama et al., 1986;Shinozaki et al., 1986; Hiratsuka et al., 1989; Evrard et al., 1990; Hallick et al., 1993; Wakasugi et al., 1994 Wakasugi et al., , 1997Kowallik et al., 1995;Maier et al., 1995;Reith and Munholland, 1995; Douglas and Penny, 1999;Sato et al., 1999; Turmel et al., 1999;Hupfer et al., 2000;Lemieux et al., 2000), the functions of most of the major open reading frames of chloroplast DNA have now been studied. The ability to perform reverse genetics with tobacco and Chlamydomonas chloroplasts has contributed greatly to this process. However, this strategy, which consists mainly of the phenotypic characterization of mutants inactivated for the gene under study, can be unsuccessful in two cases: (1) when the gene product is required for cell viability, in which case homoplasmic transformation cannot be obtained, and (2) when homoplasmic transformants do not display any clear-cut mutant phenotype under laboratory conditions. In both cases, this may preclude a reliable functional characterization of the gene and its product.ycf9 , which is predicted to encode a 6.5-kD protein with two putative membrane-spanning segments, is an interesting case because attempts to inactivate the gene have yielded widely different results ranging from potential lethality to 1 These authors cont...

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Section: Discussionsupporting

confidence: 81%

The Chloroplast Gene ycf9 Encodes a Photosystem II (PSII) Core Subunit, PsbZ, That Participates in PSII Supramolecular Architecture

Świątek¹,

Kuras²,

Sokilenko³

et al. 2001

The Plant Cell

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“…Also, the study by Schneider and Erez (2006) (23) found no effect of CO 2 dosing on rates of photosynthesis and respiration, but similar to Reynaud et al The productivity responses of the CCA and corals to CO 2 dosing are likely to be a result of a series of opposing mechanisms. Initial loss of pigmentation in the corals can result in increased productivity per remnant symbiont or per chlorophyll because of subtle increases in temperature or an increased internal light field (29,30). As severe bleaching takes over, the decline in the symbiont population (or the chlorophyll pool) overrides the increased photosynthetic efficiencies, leading to a drop in areal productivity.…”

Section: Discussionmentioning

confidence: 99%

Ocean acidification causes bleaching and productivity loss in coral reef builders

Anthony

Kline

Díaz-Pulido

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

1,043

894

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Ocean acidification represents a key threat to coral reefs by reducing the calcification rate of framework builders. In addition, acidification is likely to affect the relationship between corals and their symbiotic dinoflagellates and the productivity of this association. However, little is known about how acidification impacts on the physiology of reef builders and how acidification interacts with warming. Here, we report on an 8-week study that compared bleaching, productivity, and calcification responses of crustose coralline algae (CCA) and branching (Acropora) and massive (Porites) coral species in response to acidification and warming. Using a 30-tank experimental system, we manipulated CO2 levels to simulate doubling and three-to fourfold increases [Intergovernmental Panel on Climate Change (IPCC) projection categories IV and VI] relative to present-day levels under cool and warm scenarios. Results indicated that high CO2 is a bleaching agent for corals and CCA under high irradiance, acting synergistically with warming to lower thermal bleaching thresholds. We propose that CO2 induces bleaching via its impact on photoprotective mechanisms of the photosystems. Overall, acidification impacted more strongly on bleaching and productivity than on calcification. Interestingly, the intermediate, warm CO 2 scenario led to a 30% increase in productivity in Acropora, whereas high CO 2 lead to zero productivity in both corals. CCA were most sensitive to acidification, with high CO 2 leading to negative productivity and high rates of net dissolution. Our findings suggest that sensitive reef-building species such as CCA may be pushed beyond their thresholds for growth and survival within the next few decades whereas corals will show delayed and mixed responses.climate change ͉ global warming ͉ carbon dioxide ͉ Great Barrier Reef T he concentrations of atmospheric CO 2 predicted for this century present two major challenges for coral-reef building organisms (1). Firstly, rising sea surface temperatures associated with CO 2 increase will lead to an increased frequency and severity of coral bleaching events (large-scale disintegration of the critically important coral-dinoflagellate symbiosis) with negative consequences for coral survival, growth, and reproduction (2). Secondly, Ͼ30% of the CO 2 emitted to the atmosphere by human activities is taken up by the ocean (3, 4), lowering the pH of surface waters to levels that will potentially compromise or prevent calcium carbonate accretion by organisms including reef corals (1, 5), calcifying algae (6, 7) and a diverse range of other organisms (8). Ocean acidification research has focused mainly on the consequences of shifting ocean chemistry toward suboptimal saturation states of aragonite and calcite (9) and how this will affect the calcification processes of organisms in the pelagic (10) and benthic (11, 12) environments. Previous studies have shown dissolution of coral skeletons (13) and reduced rates of reef calcification (14) with increasing CO 2 concentrations. Ocea...

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“…It has been suggested that in the presence of reduced Q A charge recombination reactions occur that can lead to the formation of a long-lived chlorophyll triplet state and consequently to the production of 1 O 2 , which is believed to be responsible for photodamage (70,71). The redox state of Q A depends on a balance between light absorption by the antennae and the redox state of the PQ pool (15,72). This balance is compromised in the PsaF-deficient strains, leading to over-reduction of Q A , but partially restored in the suppressor strain by lowering the excitation energy input through the antennae.…”

Section: Discussionmentioning

confidence: 99%

“…In Chlamydomonas reinhardtii the absorbance crosssections of the two photosystems are nearly balanced in state I and change to 0.15 for PSII and 0.85 for PSI in state II (11). In algae long term responses may result in a reduction of the PSII antenna size (12)(13)(14)(15)(16). Alternatively, photoautotrophs could adapt by enhancing their electron-consuming sinks through a selective increase in the capacity of CO 2 assimilation or photorespiration (17).…”

mentioning

confidence: 99%

Limitation in Electron Transfer in Photosystem I Donor Side Mutants of Chlamydomonas reinhardtii

Hippler¹,

Biehler²,

Krieger‐Liszkay³

et al. 2000

Journal of Biological Chemistry

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Strains of Chlamydomonas reinhardtii lacking thePsaF gene or containing the mutation K23Q within the N-terminal part of PsaF are sensitive to high light (>400 E m ؊2 s ؊1 ) under aerobic conditions. In vitro experiments indicate that the sensitivity to high light of the isolated photosystem I (PSI) complex from wild type and from PsaF mutants is similar. In vivo measurements of photochemical quenching and oxygen evolution show that impairment of the donor side of PSI in the PsaF mutants leads to a diminished linear electron transfer and/or a decrease of photosystem II (PSII) activity in high light. Thermoluminescence measurements indicate that the PSII reaction center is directly affected under photo-oxidative stress when the rate of electron transfer becomes limiting in the PsaF-deficient strain and in the PsaF mutant K23Q. We have isolated a high light-resistant PsaF-deficient suppressor strain that has a high chlorophyll a/b ratio and is affected in the assembly of light-harvesting complex. These results indicate that under high light a functionally intact donor side of PSI is essential for protection of C. reinhardtii against photo-oxidative damage when the photosystems are properly connected to their light-harvesting antennae.Photosynthesis is driven by light. Photons are absorbed by pigments of the light harvesting chlorophyll-carotenoid-protein complexes that are associated with the membrane embedded photosynthetic reaction centers. Excitation energy can be transferred to the reaction centers where it induces charge separation across the membrane. This leads to a series of electron transfer reactions resulting in oxidation of water and the production of chemical energy in the form of ATP and NADPH, which are used for CO 2 fixation. If the absorption of light exceeds the capacity of photosynthetic energy consumption, over-reduction of the electron transport carriers and increase of the lifetime of excited states in the light-harvestingantennae occur. Over-reduction of the electron carriers can lead to photo-oxidative damage by reactive oxygen species. O 2 can be directly reduced by PSI 1 (1) generating superoxide anion radical (O 2 . ) and other reactive oxygen species. Increase in the lifetime of excited singlet chlorophyll increases the probability of triplet chlorophyll formation, which can react with O 2 to produce 1 O 2 (2, 3). Reactive oxygen species cause photo-oxidative damage, especially to PSII, which is considered to be the primary target for photoinhibition (4 -6). Thus, mechanisms that balance energy input through photochemistry with energy consumption through CO 2 assimilation and other metabolic pathways are essential for plant survival.Mechanisms that balance energy input and consumption can be divided into short and long term responses. Short term responses include nonphotochemical dissipation of excess energy (7, 8) and reduction of energy transfer to PSII through state transition, a process that leads to a redistribution of excitation energy to PSI by a reorganization of the antennae (...

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Photosystem II Excitation Pressure and Development of Resistance to Photoinhibition (I. Light-Harvesting Complex II Abundance and Zeaxanthin Content in Chlorella vulgaris)

Cited by 185 publications

References 21 publications

The Chloroplast Gene ycf9 Encodes a Photosystem II (PSII) Core Subunit, PsbZ, That Participates in PSII Supramolecular Architecture

The Chloroplast Gene ycf9 Encodes a Photosystem II (PSII) Core Subunit, PsbZ, That Participates in PSII Supramolecular Architecture

Ocean acidification causes bleaching and productivity loss in coral reef builders

Limitation in Electron Transfer in Photosystem I Donor Side Mutants of Chlamydomonas reinhardtii

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