WRINKLED1 and ACYL-COA:DIACYLGLYCEROL ACYLTRANSFERASE1 regulate tocochromanol metabolism in Arabidopsis.

Autor: Pellaud S; Department of Biology, University of Fribourg, Chemin du musée 10, CH-1700, Fribourg, Switzerland., Bory A; Department of Biology, University of Fribourg, Chemin du musée 10, CH-1700, Fribourg, Switzerland., Chabert V; Department of Chemistry, University of Fribourg, Chemin du musée, 9, CH-1700, Fribourg, Switzerland., Romanens J; Department of Biology, University of Fribourg, Chemin du musée 10, CH-1700, Fribourg, Switzerland., Chaisse-Leal L; Department of Biology, University of Fribourg, Chemin du musée 10, CH-1700, Fribourg, Switzerland., Doan AV; Department of Biology, University of Fribourg, Chemin du musée 10, CH-1700, Fribourg, Switzerland., Frey L; Department of Biology, University of Fribourg, Chemin du musée 10, CH-1700, Fribourg, Switzerland., Gust A; Department of Plant Biochemistry, ZMBP - Center for Plant Molecular Biology, University of Tübingen, Auf der Morgenstelle 32, D-72076, Tübingen, Germany., Fromm KM; Department of Chemistry, University of Fribourg, Chemin du musée, 9, CH-1700, Fribourg, Switzerland., Mène-Saffrané L; Department of Biology, University of Fribourg, Chemin du musée 10, CH-1700, Fribourg, Switzerland.
Jazyk: angličtina
Zdroj: The New phytologist [New Phytol] 2018 Jan; Vol. 217 (1), pp. 245-260. Date of Electronic Publication: 2017 Nov 03.
DOI: 10.1111/nph.14856
Abstrakt: Photosynthetic organisms such as plants, algae and some cyanobacteria synthesize tocochromanols, a group of compounds that encompasses tocopherols and tocotrienols and that exhibits vitamin E activity in animals. While most vitamin E biosynthetic genes have been identified in plant genomes, regulatory genes controlling tocopherol accumulation are currently unknown. We isolated by forward genetics Arabidopsis enhanced vitamin E (eve) mutants that overaccumulate the classic tocopherols and plastochromanol-8, and a tocochromanol unknown in this species. We mapped eve1 and eve4, and identified the unknown Arabidopsis tocochromanol by using a combination of analytical tools. In addition, we determined its biosynthetic pathway with a series of tocochromanol biosynthetic mutants and transgenic lines. eve1 and eve4 are two seed lipid mutants affecting the WRINKLED1 (WRI1) and ACYL-COA:DIACYLGLYCEROL ACYLTRANSFERASE1 (DGAT1) genes, respectively. The unknown tocochromanol is 11'-12' γ-tocomonoenol, whose biosynthesis is VITAMIN E 1 (VTE1) - and VTE2-dependent and is initiated by the condensation of homogentisate (HGA) and tetrahydrogeranylgeranyl pyrophosphate. This study identifies the first two regulatory genes, WRI1 and DGAT1, that control the synthesis of all tocochromanol forms in seeds, and shows the existence of a metabolic trade-off between lipid and tocochromanol metabolisms. Moreover, it shows that Arabidopsis possesses a tocomonoenol biosynthetic pathway that competes with tocopherol synthesis.
(© 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.)
Databáze: MEDLINE
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