Location: Chemistry ResearchTitle: Arabidopsis 4-COUMAROYL-COA LIGASE 8 contributes to the biosynthesis of the benzenoid ring of coenzyme Q in peroxisomes
|SOUBEYRAND, ERIC - University Of Florida|
|KELLY, MEGAN - University Of Florida|
|BERNERT, ANN - University Of Florida|
|KEENE, SHEA - University Of Florida|
|LATIMER, SCOTT - University Of Florida|
|JOHNSON, TIMOTHY - University Of Florida|
|ELOWSKY, CHRISTIAN - University Of Nebraska|
|COLQUHOUN, THOMAS - University Of Florida|
|BASSET, GILLES - University Of Florida|
Submitted to: Biochemical Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/5/2019
Publication Date: 11/27/2019
Citation: Soubeyrand, E., Kelly, M., Bernert, A.C., Keene, S.A., Latimer, S., Johnson, T.S., Elowsky, C., Colquhoun, T.A., Block, A.K., Basset, G.J. 2019. Arabidopsis 4-COUMAROYL-COA LIGASE 8 contributes to the biosynthesis of the benzenoid ring of coenzyme Q in peroxisomes. Biochemical Journal. 476(22):3521-3532. https://doi.org/10.1042/BCJ20190688.
Interpretive Summary: Ubiquinone or coenzyme Q (CoQ) is a molecule that is necessary for both plants and animals to convert food into energy. CoQ is a popular dietary supplement in humans due to its role in energy use and its antioxidant properties. Plants with enhanced CoQ level are potentially both more stress resistant and have enhanced nutraceutical value. Researchers from USDA-ARS Center for Medical, Agricultural, and Veterinary Entomology (Gainesville, FL), the University of Florida and the University of Nebraska-Lincoln have identified a gene in plants that is involved in the production of CoQ and have shown that increased levels of this gene lead to up to 150% higher levels of CoQ in the plant. These research results demonstrate that plants with elevated CoQ production can be achieved and provide a framework for producing elevated CoQ in agricultural commodities.
Technical Abstract: Plants have evolved the ability to derive the benzenoid moiety of the respiratory cofactor and antioxidant, ubiquinone (coenzyme Q), either from the beta-oxidative metabolism of p-coumarate or from the peroxidative cleavage of kaempferol. Here, isotopic feeding assays, gene coexpression analysis and reverse genetics identified Arabidopsis 4-COUMARATE-COA LIGASE 8 (At5g38120) as a contributor to the beta-oxidation of p-coumarate for ubiquinone biosynthesis. A corresponding T-DNA knockout displayed a 20% decrease in ubiquinone content compared with wild-type plants, while 4-COUMARATE-COA LIGASE 8 overexpression boosted ubiquinone content up to 150% of control level. Similarly, the isotopic enrichment of ubiquinone's ring was decreased by 28% in the 4-coumarate-coa ligase 8 knockout as compared to wild-type controls when Phe-[Ring-13C6] was fed to the plants. This metabolic blockage could be by-passed via the exogenous supply of 4-hydroxybenzoate, the product of p-coumarate beta-oxidation. Arabidopsis 4-COUMARATE-COA LIGASE 8 displays a canonical peroxisomal targeting sequence type 1 and confocal microscopy experiments using fused fluorescent reporters demonstrated that this enzyme is imported into peroxisomes. Time course feeding assays using Phe-[Ring-13C6] indicated that light is a major regulator of the de novo biosynthesis of ubiquinone in Arabidopsis leaves. Evidence is shown that 4-COUMARATE-COA LIGASE 8 and kaempferol catabolism do not contribute to such a regulation while At4g19010, which encodes for a 4-COUMARATE-COA LIGASE 8 homolog, does.