%0 Journal Article
%A Fiore, A.
%A Dall'Osto, L.
%A Cazzaniga, S.
%A Diretto, G.
%A Giuliano, G.
%A Bassi, R.
%T A quadruple mutant of Arabidopsis reveals a novel activity for LUT1/CYP97C1 in carotene hydroxylation and a regulatory role of xanthophylls on determination of the PSI/PSII ratio
%J BMC plant biology
%V 12
%@ 1471-2229
%C London
%I BioMed Central
%M PreJuSER-22168
%P 50
%D 2012
%Z Work supported by the Italian ministry of Research, special fund for basic research (PRIN 2008XB774B), and by the European Commission, Metapro project.
%X 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.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.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.
%K Arabidopsis: genetics
%K Arabidopsis: metabolism
%K Arabidopsis Proteins: genetics
%K Arabidopsis Proteins: metabolism
%K Mutation
%K Photosystem I Protein Complex: metabolism
%K Photosystem II Protein Complex: metabolism
%K Xanthophylls: metabolism
%K beta Carotene: metabolism
%K Arabidopsis Proteins (NLM Chemicals)
%K Photosystem I Protein Complex (NLM Chemicals)
%K Photosystem II Protein Complex (NLM Chemicals)
%K Xanthophylls (NLM Chemicals)
%K beta Carotene (NLM Chemicals)
%K J (WoSType)
%F PUB:(DE-HGF)16
%9 Journal Article
%$ pmid:22513258
%2 pmc:PMC3349566
%U <Go to ISI:>//WOS:000304009900001
%R 10.1186/1471-2229-12-50
%U https://juser.fz-juelich.de/record/22168