This title appears in the Scientific Report :
2012
Please use the identifier:
http://dx.doi.org/10.1186/1471-2229-12-50 in citations.
Please use the identifier: http://hdl.handle.net/2128/7510 in citations.
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
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
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...
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Personal Name(s): | Fiore, A. |
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Dall'Osto, L. / Cazzaniga, S. / Diretto, G. / Giuliano, G. / Bassi, R. | |
Contributing Institute: |
Pflanzenwissenschaften; IBG-2 |
Published in: | BMC plant biology, 12 (2012) S. 50 |
Imprint: |
London
BioMed Central
2012
|
Physical Description: |
50 |
PubMed ID: |
22513258 |
DOI: |
10.1186/1471-2229-12-50 |
Document Type: |
Journal Article |
Research Program: |
Terrestrische Umwelt |
Series Title: |
BMC Plant Biology
12 |
Subject (ZB): | |
Link: |
Get full text OpenAccess |
Publikationsportal JuSER |
Please use the identifier: http://hdl.handle.net/2128/7510 in citations.
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. |