A role for B,B-xanthophylls in Arabidopsis UV-B photoprotection

LUCIO D´ANDREA; EDUARDO JOSE RODRIGUEZ; JULIA EMILIANI; EVANGELINA MAULIÓN; PAULA CASATI; JULIA EMILIANI; EVANGELINA MAULIÓN; PAULA CASATI; MARÍA LORENA FALCONE-FERREYRA; MANUEL RODRIGUEZ CONCEPCIÓN; MARÍA LORENA FALCONE-FERREYRA; MANUEL RODRIGUEZ CONCEPCIÓN; LUCIO D´ANDREA; EDUARDO JOSE RODRIGUEZ

JOURNAL OF EXPERIMENTAL BOTANY

OXFORD UNIV PRESS

Lugar: Oxford; Año: 2018

0022-0957

Plastidial isoprenoids, such as carotenoids and tocopherols, are important anti-oxidant metabolites synthesized inplastids from precursors generated by the methylerythritol 4-phosphate (MEP) pathway. In this study, we found thatirradiation of Arabidopsis thaliana plants with UV-B caused a strong increase in the accumulation of the photoprotectivexanthophyll zeaxanthin but also resulted in slightly higher levels of γ-tocopherol. Plants deficient in theMEP enzymes 1-deoxy-D-xylulose 5-phosphate synthase and 1-hydroxy-2-methyl-2-butenyl 4-diphosphate synthaseshowed a general reduction in both carotenoids and tocopherols and this was associated with increased DNA damageand decreased photosynthesis after exposure to UV-B. Genetic blockage of tocopherol biosynthesis did notaffect DNA damage accumulation. In contrast, lut2 mutants that accumulate β,β-xanthophylls showed decreased DNAdamage 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 oxidativedamage and increased expression of DNA-repair enzymes, suggesting that this may be a mechanism for these plantsto decrease DNA damage. In addition, in vitro experiments also provided evidence that β,β-xanthophylls can directlyprotect against DNA damage by absorbing radiation. Together, our results suggest that xanthophyll-cycle carotenoidsthat protect against excess illumination may also contribute to protection against UV-B.