Xanthophyll biosynthetic mutants of Arabidopsis thaliana: Altered nonphotochemical quenching of chlorophyll fluorescence is due to changes in Photosystem II antenna size and stability

Heiko Lokstein, Li Tian, Jürgen E W Polle, Dean DellaPenna

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130 Scopus citations

Abstract

Xanthophylls (oxygen derivatives of carotenes) are essential components of the plant photosynthetic apparatus. Lutein, the most abundant xanthophyll, is attached primarily to the bulk antenna complex, light-harvesting complex (LHC) II. We have used mutations in Arabidopsis thaliana that selectively eliminate (and substitute) specific xanthophylls in order to study their function(s) in vivo. These include two lutein-deficient mutants, lut1 and lut2, the epoxy xanthophyll-deficient aba1 mutant and the lut2aba1 double mutant. Photosystem stoichiometry, antenna sizes and xanthophyll cycle activity have been related to alterations in nonphotochemical quenching of chlorophyll fluorescence (NPQ). Nondenaturing polyacrylamide gel electrophoresis indicates reduced stability of trimeric LHC II in the absence of lutein (and/or epoxy xanthophylls). Photosystem (antenna) size and stoichiometry is altered in all mutants relative to wild type (WT). Maximal ΔpH-dependent NPQ (qE) is reduced in the following order: WT>aba1>lut1≈lut2>lut2aba1, paralleling reduction in Photosystem (PS) II antenna size. Finally, light-activation of NPQ shows that zeaxanthin and antheraxanthin present constitutively in lut mutants are not qE active, and hence, the same can be inferred of the lutein they replace. Thus, a direct involvement of lutein in the mechanism of qE is unlikely. Rather, altered NPQ in xanthophyll biosynthetic mutants is explained by disturbed macro-organization of LHC II and reduced PS II-antenna size in the absence of the optimal, wild-type xanthophyll composition. These data suggest the evolutionary conservation of lutein content in plants was selected for due to its unique ability to optimize antenna structure, stability and macro-organization for efficient regulation of light-harvesting under natural environmental conditions.

Original languageEnglish (US)
Pages (from-to)309-319
Number of pages11
JournalBiochimica et Biophysica Acta - Bioenergetics
Volume1553
Issue number3
DOIs
StatePublished - Feb 15 2002
Externally publishedYes

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Keywords

  • Antenna size
  • Arabidopsis thaliana
  • Carotenoid
  • Lutein
  • Nonphotochemical quenching of chlorophyll fluorescence
  • Photoprotection
  • Xanthophyll

ASJC Scopus subject areas

  • Biophysics

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