The roles of specific xanthophylls in light utilization

Kalituho, Ljudmila; Rech, Jennifer; Jahns, Peter

doi:10.1007/s00425-006-0356-3

Cited by 67 publications

(58 citation statements)

References 50 publications

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“…Because this antioxidative activity takes place in a mutant devoid of LHCIIs, it is not restricted to triplet Chl and 1 O 2 quenching in the PSII antennae, as suggested by some authors (Kalituho et al, 2006). It is also unlikely that the main effect of zeaxanthin was in the PSII core antennae of ch1 thylakoids.…”

Section: Zeaxanthin Protects Ch1 Thylakoid Membranes By a Mechanism Tmentioning

confidence: 81%

Zeaxanthin Has Enhanced Antioxidant Capacity with Respect to All Other Xanthophylls in Arabidopsis Leaves and Functions Independent of Binding to PSII Antennae

2007

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The ch1 mutant of Arabidopsis (Arabidopsis thaliana) lacks chlorophyll (Chl) b. Leaves of this mutant are devoid of photosystem II (PSII) Chl-protein antenna complexes and have a very low capacity of nonphotochemical quenching (NPQ) of Chl fluorescence. Lhcb5 was the only PSII antenna protein that accumulated to a significant level in ch1 mutant leaves, but the apoprotein did not assemble in vivo with Chls to form a functional antenna. The abundance of Lhca proteins was also reduced to approximately 20% of the wild-type level. ch1 was crossed with various xanthophyll mutants to analyze the antioxidant activity of carotenoids unbound to PSII antenna. Suppression of zeaxanthin by crossing ch1 with npq1 resulted in oxidative stress in high light, while removing other xanthophylls or the PSII protein PsbS had no such effect. The tocopherol-deficient ch1 vte1 double mutant was as sensitive to high light as ch1 npq1, and the triple mutant ch1 npq1 vte1 exhibited an extreme sensitivity to photooxidative stress, indicating that zeaxanthin and tocopherols have cumulative effects. Conversely, constitutive accumulation of zeaxanthin in the ch1 npq2 double mutant led to an increased phototolerance relative to ch1. Comparison of ch1 npq2 with another zeaxanthinaccumulating mutant (ch1 lut2) that lacks lutein suggests that protection of polyunsaturated lipids by zeaxanthin is enhanced when lutein is also present. During photooxidative stress, a-tocopherol noticeably decreased in ch1 npq1 and increased in ch1 npq2 relative to ch1, suggesting protection of vitamin E by high zeaxanthin levels. Our results indicate that the antioxidant activity of zeaxanthin, distinct from NPQ, can occur in the absence of PSII light-harvesting complexes. The capacity of zeaxanthin to protect thylakoid membrane lipids is comparable to that of vitamin E but noticeably higher than that of all other xanthophylls of Arabidopsis leaves.

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Section: Zeaxanthin Protects Ch1 Thylakoid Membranes By a Mechanism Tmentioning

confidence: 81%

Zeaxanthin Has Enhanced Antioxidant Capacity with Respect to All Other Xanthophylls in Arabidopsis Leaves and Functions Independent of Binding to PSII Antennae

2007

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“…The lower values of NPQ in the two zeaxanthinaccumulating mutants have been suggested to arise from the prequenching of F m (for definitions of fluorescence terms, see "Materials and Methods") caused by sustained zeaxanthin-mediated NPQ (Dall'Osto et al, 2005;Kalituho et al, 2006b). The presence of such prequenching was supported by the lower F v /F m values for dark-adapted npq2 and lut2npq2 plants compared with wild-type plants (Table V).…”

Section: Absence Of Lutein Disrupts the Kinetics And Amplitude Of Qementioning

confidence: 83%

The Zeaxanthin-Independent and Zeaxanthin-Dependent qE Components of Nonphotochemical Quenching Involve Common Conformational Changes within the Photosystem II Antenna in Arabidopsis

et al. 2008

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The light-harvesting antenna of higher plant photosystem II (LHCII) has the intrinsic capacity to dissipate excess light energy as heat in a process termed nonphotochemical quenching (NPQ). Recent studies suggest that zeaxanthin and lutein both contribute to the rapidly relaxing component of NPQ, qE, possibly acting in the minor monomeric antenna complexes and the major trimeric LHCII, respectively. To distinguish whether zeaxanthin and lutein act independently as quenchers at separate sites, or alternatively whether zeaxanthin fulfills an allosteric role regulating lutein-mediated quenching, the kinetics of qE and the qE-related conformational changes (DA 535 ) were compared in Arabidopsis (Arabidopsis thaliana) mutant/antisense plants with altered contents of minor antenna (kolhcb6, aslhcb4), trimeric LHCII (aslhcb2), lutein (lut2, lut2npq1, lut2npq2), and zeaxanthin (npq1, npq2). The kinetics of the two components of NPQ induction arising from zeaxanthin-independent and zeaxanthin-dependent qE were both sensitive to changes in the protein composition of the photosystem II antenna. The replacement of lutein by zeaxanthin or violaxanthin in the internal Lhcb protein-binding sites affected the kinetics and relative amplitude of each component as well as the absolute chlorophyll fluorescence lifetime. Both components of qE were characterized by a conformational change leading to nearly identical absorption changes in the Soret region that indicated the involvement of the LHCII lutein 1 domain. Based on these observations, we suggest that both components of qE arise from a common quenching mechanism based upon a conformational change within the photosystem II antenna, optimized by Lhcb subunit-subunit interactions and tuned by the synergistic effects of external and internally bound xanthophylls.

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“…Similar conclusions can be drawn from the determination of the initial rates of electron transport through PSII showing lowest rates for pgr1 and npq2 (Table I). The reduced rate of electron transport in npq2 in comparison with the wild type might be related to sustained energy dissipation due to the accumulation of high levels of Zx in this mutant (Kalituho et al, 2007). It can thus be assumed that, in comparison with wild-type plants, lumen acidification is limited in pgr1 and possibly npq2, but not in npq1 and npq4.…”

Section: Vx De-epoxidation and Electron Transport Rates During Npq Fomentioning

confidence: 98%

“…2 and 4), although maximal amounts of Zx are present in npq2 under all conditions. The even slower rate of NPQ formation in npq2 might reflect the less efficient utilization of absorbed light energy due to sustained heat dissipation of excitation energy (Kalituho et al, 2007), resulting in a reduced electron transport rate and by that of lumen acidification in npq2 (Table I).…”

Section: Kinetics Of Qe Formationmentioning

confidence: 99%

“…The residual Zx-independent qE that is detectable in npq1 plants from Arabidopsis has been shown to vary from about 10% to 20% (Niyogi et al, 1998;Pogson and Rissler, 2000;Kalituho et al, 2007) up to nearly 50% (Dall'Osto et al, 2005) of the respective wild-type levels. Interestingly, absolute values of qE in npq1 were in all cases in the range from 0.2 to 0.4 in those former studies, which is similar to the magnitude of the transient qE TR determined in this work for npq1 (Figs.…”

Section: Energy Dissipation and The Role Of Zxmentioning

confidence: 99%

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The Transiently Generated Nonphotochemical Quenching of Excitation Energy in Arabidopsis Leaves Is Modulated by Zeaxanthin

2007

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Upon the transition of dark-adapted plants to low light, the energy-dependent quenching (qE) of excitation energy is only transiently induced due to the only transient generation of the transthylakoid pH gradient. We investigated the transient qE (qE TR ) in different Arabidopsis (Arabidopsis thaliana) mutants. In dark-adapted plants, qE TR was absent in the npq4 mutant (deficient in the PsbS protein) and the pgr1 mutant (restricted in lumen acidification). In comparison with wild-type plants, qE TR was reduced in the zeaxanthin (Zx)-deficient npq1 mutant and increased in the Zx-accumulating npq2 mutant. After preillumination of plants (to allow the synthesis of large amounts of Zx), the formation and relaxation of qE TR was accelerated in all plants (except for npq4) in comparison with the respective dark-adapted plants. The extent of qE TR , however, was unchanged in npq1 and npq4, decreased in npq2, but increased in wild-type and pgr1 plants. Even in presence of high levels of Zx, qE TR in pgr1 mutants was still lower than that in wild-type plants. In the presence of the uncoupler nigericin, qE TR was completely abolished in all genotypes. Thus, the transient qE TR shows essentially the same characteristics as the steady-state qE; it is strictly dependent on the PsbS protein and a low lumen pH, but the extent of qE TR is largely modulated by Zx. These results indicate that qE TR does not represent a different quenching mechanism in comparison with the steady-state qE, but simply reflects the response of qE to the dynamics of the lumen pH during light activation of photosynthesis.

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The roles of specific xanthophylls in light utilization

Cited by 67 publications

References 50 publications

Zeaxanthin Has Enhanced Antioxidant Capacity with Respect to All Other Xanthophylls in Arabidopsis Leaves and Functions Independent of Binding to PSII Antennae

Zeaxanthin Has Enhanced Antioxidant Capacity with Respect to All Other Xanthophylls in Arabidopsis Leaves and Functions Independent of Binding to PSII Antennae

The Zeaxanthin-Independent and Zeaxanthin-Dependent qE Components of Nonphotochemical Quenching Involve Common Conformational Changes within the Photosystem II Antenna in Arabidopsis

The Transiently Generated Nonphotochemical Quenching of Excitation Energy in Arabidopsis Leaves Is Modulated by Zeaxanthin

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