Carotenoids Assist in Cyanobacterial Photosystem II Assembly and Function

Zakar, Tomáš; Laczkó-Dobos, Hajnalka; Tóth, Tünde; Gombos, Zoltán

doi:10.3389/fpls.2016.00295

Cited by 100 publications

(53 citation statements)

References 56 publications

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“…We measured the induction of YNPQ under blue actinic and measuring light, absorbed primarily through chlorophyll. Cyanobacteria show stronger variations in YNPQ measured using light absorbed through the phycobilisome (Gorbunov et al, 2011) or through carotenoids (Zakar et al, 2016).…”

Section: Resultsmentioning

confidence: 99%

“…In contrast we found a lack of response of σ PSII ′ to a comparable magnitude of YNPQ induction under excess blue light ( Figure 4B). Our measures under 455 nm blue light, delivered to the small chl a absorption cross section associated with cyanobacterial PSII, largely bypass mechanisms including the Orange Carotenoid Protein that modulate excitation delivery through the phycobilisome (Gorbunov et al, 2011;Zakar et al, 2016), which could generate detectable changes in σ PSII ′ . In Ostreococcus (Figure 4C) cultures from growth-limiting or growth-saturating light showed a common Y-axis intercept, showing no significant acclimatory change in σ PSII between the two growth light intensities.…”

Section: Figure 4 Presents the Responses Of σ Psiimentioning

confidence: 99%

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Phytoplankton σPSII and Excitation Dissipation; Implications for Estimates of Primary Productivity

Lavaud

Perkins

et al. 2018

Front. Mar. Sci.

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The effective absorption cross section for photochemistry of Photosystem II in the light (σ PSII ′ ) comprises the probability of light capture by Photosystem II and the quantum yield for subsequent photochemistry. σ PSII ′ is used to model photosynthesis and aquatic productivity, and phytoplankters regulate σ PSII ′ to mitigate over-or under-excitation of Photosystem II. We used diverse phytoplankton taxa to compare short and long term changes in σ PSII ′ with the induction of the yield of non-photochemical quenching (YNPQ) of chlorophyll fluorescence, a measure of regulated excitation dissipation. In two picocyanobacteria σ PSII ′ showed no decline upon induction of moderate YNPQ, above light levels sufficient for saturation of electron transport. In the eukaryotic chl a/b Ostreococcus and the chl a/c diatom Thalassiosira, induction of non-photochemical quenching was stronger after growth under saturating light, an acclimation attributable to increased xanthophyll cycle pigment content. Across short and longer-term light histories to induce or relax regulatory processes Ostreococcus and Thalassiosira showed proportional variations between the level of YNPQ and the down regulation of σ PSII ′ . The proportional down regulation of σ PSII ′ was, however, significantly smaller than the amplitude of YNPQ induction. For the eukaryotes we can predict changes in σ PSII ′ , useful for modeling electron transport, productivity and acclimation, from measures of YNPQ, which are accessible from fluorescence yield measures that do not include σ PSII ′ . This useful relation, however, does not extend to the tested prokaryotes, possibly as a result of differential violations of the rate constant assumptions that underlie the calculated YNPQ parameter.

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Section: Resultsmentioning

confidence: 99%

Section: Figure 4 Presents the Responses Of σ Psiimentioning

confidence: 99%

Phytoplankton σPSII and Excitation Dissipation; Implications for Estimates of Primary Productivity

Lavaud

Perkins

et al. 2018

Front. Mar. Sci.

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“…Cars are multi-functional (Zakar et al 2016). They take part in the light-harvesting processes (Stamatakis et al 2014) and assembly of the PSII photosynthetic complex (Sozer et al 2010), modulate membrane structures and protect them from environmental stress factors (Varkonyi et al 2002; Domonkos et al 2009).…”

Section: Introductionmentioning

confidence: 99%

“…A recent study of tetrameric PSI suggests that these supercomplexes may be stabilized by Cars or lipids (Semchonok et al 2016). Carotenes may also influence the structure and function of phycobilisomes (Vajravel et al 2016; Toth et al 2015; Zakar et al 2016). Cars are also vital for the PSII function (Zakar et al 2016).…”

Section: Introductionmentioning

confidence: 99%

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Lipid and carotenoid cooperation-driven adaptation to light and temperature stress in Synechocystis sp. PCC6803

Zakar

Herman

Vajravel

et al. 2017

Biochimica et Biophysica Acta (BBA) - Bioenergetics

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Polyunsaturated lipids are important components of photosynthetic membranes. Xanthophylls are the main photoprotective agents, can assist in protection against light stress, and are crucial in the recovery from photoinhibition. We generated the xanthophyll- and polyunsaturated lipid-deficient ROAD mutant of Synechocystis sp. PCC6803 (Synechocystis) in order to study the little-known cooperative effects of lipids and carotenoids (Cars). Electron microscopic investigations confirmed that in the absence of xanthophylls the S-layer of the cellular envelope is missing. In wild-type (WT) cells, as well as the xanthophyll-less (RO), polyunsaturated lipid-less (AD), and the newly constructed ROAD mutants the lipid and Car compositions were determined by MS and HPLC, respectively. We found that, relative to the WT, the lipid composition of the mutants was remodeled and the Car content changed accordingly. In the mutants the ratio of non-bilayer-forming (NBL) to bilayer-forming (BL) lipids were found considerably lower. Xanthophyll to β-carotene ratio increased in the AD mutant. In vitro and in vivo methods demonstrated that saturated, monounsaturated lipids and xanthophylls may stabilize the trimerization of Photosystem I (PSI). Fluorescence induction and oxygen-evolving activity measurements revealed increased light sensitivity of RO cells compared to those of the WT. ROAD showed a robust increase in light susceptibility and reduced recovery capability, especially at moderate low (ML) and moderate high (MH) temperatures, indicating a cooperative effect of xanthophylls and polyunsaturated lipids. We suggest that both lipid unsaturation and xanthophylls are required for providing the proper structure and functioning of the membrane environment that protects against light and temperature stress.

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Growth engineering of Synechococcus elongatus PCC 7942 for mixotrophy under natural light conditions for improved feedstock production

Sarnaik¹,

Pandit²,

Lali

2017

Biotechnology Progress

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Synechococcus elongatus PCC 7942 has been widely explored as cyanobacterial cell factory through genetic modifications for production of various value-added compounds. However, successful industrial scale-ups have not been reported for the system predominantly due to its obligate photoautotrophic metabolism and use of artificial light in photobioreactors. Hence, engineering the organism to perform mixotrophy under natural light could serve as an effective solution. Thus, we applied a genetically engineered strain of Synechococcus elongatus PCC 7942 expressing heterologous hexose transporter gene (galP) to perform mixotrophy under natural light in a temperature controlled environmental chamber (EC). We systematically studied the comparative performances of these transformants using autotrophy and mixotrophy, which showed 3.4 times increase in biomass productivity of mixotrophically grown transformants over autotrophs in EC. Chlorophyll a yield was found to have decreased in mixotrophic conditions, possibly indicating reduced dependency on light for energy metabolism. Although pigment yield decreases under mixotrophy, titer was found to have improved due to increased biomass productivity. Carotenoid analysis showed that zeaxanthin is the major carotenoid produced by the species which is essential for photoprotection. Our work thus demonstrates that mixotrophy under temperature controlled natural light can serve as the viable solution to improve biomass productivity of Synechococcus elongatus PCC 7942 and for commercial production of natural or engineered value added compounds from the system. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1182-1192, 2017.

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Carotenoids Assist in Cyanobacterial Photosystem II Assembly and Function

Cited by 100 publications

References 56 publications

Phytoplankton σPSII and Excitation Dissipation; Implications for Estimates of Primary Productivity

Phytoplankton σPSII and Excitation Dissipation; Implications for Estimates of Primary Productivity

Lipid and carotenoid cooperation-driven adaptation to light and temperature stress in Synechocystis sp. PCC6803

Growth engineering of Synechococcus elongatus PCC 7942 for mixotrophy under natural light conditions for improved feedstock production

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