A role for β,β-xanthophylls in Arabidopsis UV-B photoprotection
Emiliani, Julia (Universidad Nacional de Rosario. Centro de Estudios Fotosintéticos y Bioquímicos)
D'Andrea, Lucio (Centre de Recerca en Agrigenòmica)
Falcone Ferreyra, María Lorena (Universidad Nacional de Rosario. Centro de Estudios Fotosintéticos y Bioquímicos)
Maulión, Evangelina (Universidad Nacional de Rosario. Centro de Estudios Fotosintéticos y Bioquímicos)
Rodriguez, Eduardo (Universidad Nacional de Rosario. Instituto de Biología Molecular y Celular de Rosario)
Rodríguez Concepción, Manuel (Centre de Recerca en Agrigenòmica)
Casati, Paula (Universidad Nacional de Rosario. Centro de Estudios Fotosintéticos y Bioquímicos)

Data:	2018
Resum:	Plastidial isoprenoids, such as carotenoids and tocopherols, are important anti-oxidant metabolites synthesized in plastids from precursors generated by the methylerythritol 4-phosphate (MEP) pathway. In this study, we found that irradiation of Arabidopsis thaliana plants with UV-B caused a strong increase in the accumulation of the photoprotective xanthophyll zeaxanthin but also resulted in slightly higher levels of γ-tocopherol. Plants deficient in the MEP enzymes 1-deoxy-D-xylulose 5-phosphate synthase and 1-hydroxy-2-methyl-2-butenyl 4-diphosphate synthase showed a general reduction in both carotenoids and tocopherols and this was associated with increased DNA damage and decreased photosynthesis after exposure to UV-B. Genetic blockage of tocopherol biosynthesis did not affect DNA damage accumulation. In contrast, lut2 mutants that accumulate β,β-xanthophylls showed decreased DNA damage when irradiated with UV-B. Analysis of aba2 mutants showed that UV-B protection was not mediated by ABA (a hormone derived from β,β-xanthophylls). Plants accumulating β,β-xanthophylls also showed decreased oxidative damage and increased expression of DNA-repair enzymes, suggesting that this may be a mechanism for these plants to decrease DNA damage. In addition, in vitro experiments also provided evidence that β,β-xanthophylls can directly protect against DNA damage by absorbing radiation. Together, our results suggest that xanthophyll-cycle carotenoids that protect against excess illumination may also contribute to protection against UV-B.
Ajuts:	Ministerio de Economía y Competitividad BIO2015-71703-REDT Ministerio de Economía y Competitividad BIO2014-59092-P Agència de Gestió d'Ajuts Universitaris i de Recerca 2014/SGR-1434
Drets:	Tots els drets reservats.
Llengua:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Matèria:	Isoprenoids ; MEP pathway ; UV-B damage ; Violaxanthin ; Xanthophylls ; Zeaxanthin
Publicat a:	Journal of experimental botany, Vol. 69, issue 20 (Sep. 2018) , p. 4921-4933, ISSN 1460-2431

DOI: 10.1093/jxb/ery242
PMID: 29945243

Postprint 38 p, 3.3 MB

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