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http://purl.uniprot.org/citations/22513258http://www.w3.org/1999/02/22-rdf-syntax-ns#typehttp://purl.uniprot.org/core/Journal_Citation
http://purl.uniprot.org/citations/22513258http://www.w3.org/1999/02/22-rdf-syntax-ns#typehttp://purl.uniprot.org/core/Journal_Citation
http://purl.uniprot.org/citations/22513258http://www.w3.org/2000/01/rdf-schema#comment"

Background

Xanthophylls are oxygenated carotenoids playing an essential role as structural components of the photosynthetic apparatus. Xanthophylls contribute to the assembly and stability of light-harvesting complex, to light absorbance and to photoprotection. The first step in xanthophyll biosynthesis from α- and β-carotene is the hydroxylation of ε- and β-rings, performed by both non-heme iron oxygenases (CHY1, CHY2) and P450 cytochromes (LUT1/CYP97C1, LUT5/CYP97A3). The Arabidopsis triple chy1chy2lut5 mutant is almost completely depleted in β-xanthophylls.

Results

Here we report on the quadruple chy1chy2lut2lut5 mutant, additionally carrying the lut2 mutation (affecting lycopene ε-cyclase). This genotype lacks lutein and yet it shows a compensatory increase in β-xanthophylls with respect to chy1chy2lut5 mutant. Mutant plants show an even stronger photosensitivity than chy1chy2lut5, a complete lack of qE, the rapidly reversible component of non-photochemical quenching, and a peculiar organization of the pigment binding complexes into thylakoids. Biochemical analysis reveals that the chy1chy2lut2lut5 mutant is depleted in Lhcb subunits and is specifically affected in Photosystem I function, showing a deficiency in PSI-LHCI supercomplexes. Moreover, by analyzing a series of single, double, triple and quadruple Arabidopsis mutants in xanthophyll biosynthesis, we show a hitherto undescribed correlation between xanthophyll levels and the PSI-PSII ratio. The decrease in the xanthophyll/carotenoid ratio causes a proportional decrease in the LHCII and PSI core levels with respect to PSII.

Conclusions

The physiological and biochemical phenotype of the chy1chy2lut2lut5 mutant shows that (i) LUT1/CYP97C1 protein reveals a major β-carotene hydroxylase activity in vivo when depleted in its preferred substrate α-carotene; (ii) xanthophylls are needed for normal level of Photosystem I and LHCII accumulation."xsd:string
http://purl.uniprot.org/citations/22513258http://purl.org/dc/terms/identifier"doi:10.1186/1471-2229-12-50"xsd:string
http://purl.uniprot.org/citations/22513258http://purl.org/dc/terms/identifier"doi:10.1186/1471-2229-12-50"xsd:string
http://purl.uniprot.org/citations/22513258http://purl.uniprot.org/core/author"Bassi R."xsd:string
http://purl.uniprot.org/citations/22513258http://purl.uniprot.org/core/author"Bassi R."xsd:string
http://purl.uniprot.org/citations/22513258http://purl.uniprot.org/core/author"Cazzaniga S."xsd:string
http://purl.uniprot.org/citations/22513258http://purl.uniprot.org/core/author"Cazzaniga S."xsd:string
http://purl.uniprot.org/citations/22513258http://purl.uniprot.org/core/author"Dall'Osto L."xsd:string
http://purl.uniprot.org/citations/22513258http://purl.uniprot.org/core/author"Dall'Osto L."xsd:string
http://purl.uniprot.org/citations/22513258http://purl.uniprot.org/core/author"Fiore A."xsd:string
http://purl.uniprot.org/citations/22513258http://purl.uniprot.org/core/author"Fiore A."xsd:string
http://purl.uniprot.org/citations/22513258http://purl.uniprot.org/core/author"Giuliano G."xsd:string
http://purl.uniprot.org/citations/22513258http://purl.uniprot.org/core/author"Giuliano G."xsd:string
http://purl.uniprot.org/citations/22513258http://purl.uniprot.org/core/author"Diretto G."xsd:string
http://purl.uniprot.org/citations/22513258http://purl.uniprot.org/core/author"Diretto G."xsd:string
http://purl.uniprot.org/citations/22513258http://purl.uniprot.org/core/date"2012"xsd:gYear
http://purl.uniprot.org/citations/22513258http://purl.uniprot.org/core/date"2012"xsd:gYear
http://purl.uniprot.org/citations/22513258http://purl.uniprot.org/core/name"BMC Plant Biol."xsd:string
http://purl.uniprot.org/citations/22513258http://purl.uniprot.org/core/name"BMC Plant Biol."xsd:string
http://purl.uniprot.org/citations/22513258http://purl.uniprot.org/core/pages"50"xsd:string
http://purl.uniprot.org/citations/22513258http://purl.uniprot.org/core/pages"50"xsd:string
http://purl.uniprot.org/citations/22513258http://purl.uniprot.org/core/title"A quadruple mutant of Arabidopsis reveals a beta-carotene hydroxylation activity for LUT1/CYP97C1 and a regulatory role of xanthophylls on determination of the PSI/PSII ratio."xsd:string
http://purl.uniprot.org/citations/22513258http://purl.uniprot.org/core/title"A quadruple mutant of Arabidopsis reveals a beta-carotene hydroxylation activity for LUT1/CYP97C1 and a regulatory role of xanthophylls on determination of the PSI/PSII ratio."xsd:string
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