% IMPORTANT: The following is UTF-8 encoded. This means that in the presence % of non-ASCII characters, it will not work with BibTeX 0.99 or older. % Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or % “biber”. @ARTICLE{Fiore:22168, author = {Fiore, A. and Dall'Osto, L. and Cazzaniga, S. and Diretto, G. and Giuliano, G. and Bassi, R.}, title = {{A} quadruple mutant of {A}rabidopsis reveals a novel activity for {LUT}1/{CYP}97{C}1 in carotene hydroxylation and a regulatory role of xanthophylls on determination of the {PSI}/{PSII} ratio}, journal = {BMC plant biology}, volume = {12}, issn = {1471-2229}, address = {London}, publisher = {BioMed Central}, reportid = {PreJuSER-22168}, pages = {50}, year = {2012}, note = {Work supported by the Italian ministry of Research, special fund for basic research (PRIN 2008XB774B), and by the European Commission, Metapro project.}, abstract = {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.}, keywords = {Arabidopsis: genetics / Arabidopsis: metabolism / Arabidopsis Proteins: genetics / Arabidopsis Proteins: metabolism / Mutation / Photosystem I Protein Complex: metabolism / Photosystem II Protein Complex: metabolism / Xanthophylls: metabolism / beta Carotene: metabolism / Arabidopsis Proteins (NLM Chemicals) / Photosystem I Protein Complex (NLM Chemicals) / Photosystem II Protein Complex (NLM Chemicals) / Xanthophylls (NLM Chemicals) / beta Carotene (NLM Chemicals) / J (WoSType)}, cin = {IBG-2}, ddc = {580}, cid = {I:(DE-Juel1)IBG-2-20101118}, pnm = {Terrestrische Umwelt}, pid = {G:(DE-Juel1)FUEK407}, shelfmark = {Plant Sciences}, typ = {PUB:(DE-HGF)16}, pubmed = {pmid:22513258}, pmc = {pmc:PMC3349566}, UT = {WOS:000304009900001}, doi = {10.1186/1471-2229-12-50}, url = {https://juser.fz-juelich.de/record/22168}, }