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Enhanced Photoprotection by Protein-Bound vs Free Xanthophyll Pools： A Comparative Analysis of Chlorophyll b and Xanthophyll Biosynthesis Mutants

Dall'Osto, Luca ; Cazzaniga, Stefano ; Havaux, Michel ; Bassi, Roberto

Molecular plant, 2010-05, Vol.3 (3), p.576-593 [Periódico revisado por pares]

England: Elsevier Inc

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  • Título:
    Enhanced Photoprotection by Protein-Bound vs Free Xanthophyll Pools： A Comparative Analysis of Chlorophyll b and Xanthophyll Biosynthesis Mutants
  • Autor: Dall'Osto, Luca ; Cazzaniga, Stefano ; Havaux, Michel ; Bassi, Roberto
  • Assuntos: Antioxidants ; Arabidopsis - metabolism ; Arabidopsis - radiation effects ; Chlorophyll ; Chlorophyll - metabolism ; chloroplast ; Chloroplasts - metabolism ; Chloroplasts - radiation effects ; Light ; light-harvesting complexes ; photoprotection ; Reactive Oxygen Species - metabolism ; singlet oxygen ; Xanthophylls - metabolism ; Zeaxanthin ; Zeaxanthins ; 光保护作用 ; 光破坏防御 ; 叶绿素b ; 叶黄素循环 ; 玉米黄质 ; 突变体 ; 自由 ; 蛋白质
  • É parte de: Molecular plant, 2010-05, Vol.3 (3), p.576-593
  • Notas: 31-2013/Q
    Zeaxanthin
    light-harvesting complexes.
    singlet oxygen
    chloroplast
    S511
    Zeaxanthin; singlet oxygen; photoprotection; chloroplast; light-harvesting complexes.
    Q945.11
    photoprotection
    ObjectType-Article-1
    SourceType-Scholarly Journals-1
    ObjectType-Feature-2
    content type line 23
  • Descrição: When light absorbed by plants exceeds the capacity of photosynthesis, the xanthophyll violaxanthin is reversibly de-epoxidized to zeaxanthin in the so-called xanthophyll cycle. Zeaxanthin plays a key role in the protection of photosynthetic organisms against excess light, by promoting rapidly reversible （qE） and long-term （ql） quenching of excited chlorophylls, and preventing lipid oxidation. The photoprotective role of zeaxanthin, either free or bound to light-harvesting complexes （Lhcs）, has been investigated by using mutants lacking Chl b （chl） and/or specific xanthophyll species （npq, lut2）. The chl mutation causes （1） the absence of Lhcb proteins; （2） strong reduction of the feedback deexcitation （qE）; and （3） accumulation of xanthophylls as free pigments into thylakoids. Chl mutants showed extreme sensitivity to photo-oxidative stress in high light, due to higher singlet oxygen （102） release. The double mutant chlnpql was more sensitive to photo-oxidation than chl, showing that zeaxanthin does protect lipids even when free in the membrane. Nevertheless, lack of zeaxanthin had a much stronger impact on the level of lipid peroxidation in Lhcs-containing plants （WTvs npql） with respect to Lhc-less plants （chl vs chlnpql）, implying that its protective effect is enhanced by interaction with antenna proteins. It is proposed that the antioxidant capacity of zeaxanthin is empowered in the presence of PSII- LHCs-Zea complexes, while its effect on enhancement of qE only provides a minor contribution. Comparison of the sensitivity of WT vs npql plants to exogenous 102 suggests that besides the scavenging of 102, at least one additional mechanism is involved in chloroplast photoprotection.
  • Editor: England: Elsevier Inc
  • Idioma: Chinês;Inglês
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  • Realização: ABCD-USP USP   Logos de Redes Sociais: Freepik

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