title: Mutation in Brachypodium caffeic acid O-methyltransferase 6 alters stem and grain lignins and improves straw saccharification without deteriorating grain quality.
abstract: Cereal crop by-products are a promising source of renewable raw material for the production of biofuel from lignocellulose. However, their enzymatic conversion to fermentable sugars is detrimentally affected by lignins. Here the characterization of the Brachypodium Bd5139 mutant provided with a single nucleotide mutation in the caffeic acid O-methyltransferase BdCOMT6 gene is reported. This BdCOMT6-deficient mutant displayed a moderately altered lignification in mature stems. The lignin-related BdCOMT6 gene was also found to be expressed in grains, and the alterations of Bd5139 grain lignins were found to mirror nicely those evidenced in stem lignins. The Bd5139 grains displayed similar size and composition to the control. Complementation experiments carried out by introducing the mutated gene into the AtCOMT1-deficient Arabidopsis mutant demonstrated that the mutated BdCOMT6 protein was still functional. Such a moderate down-regulation of lignin-related COMT enzyme reduced the straw recalcitrance to saccharification, without compromising the vegetative or reproductive development of the plant.
authors.affiliation: INRA-UR1268 Biopolymères, Interactions, Assemblages, F-44316 Nantes, France INRA-UMR1318, Institut Jean-Pierre Bourgin, F-78026 Versailles, France.
authors.forename: Séverine
authors.initials: S
authors.lastname: Ho-Yue-Kuang
authors.affiliation: INRA-UR1268 Biopolymères, Interactions, Assemblages, F-44316 Nantes, France.
authors.forename: Camille
authors.initials: C
authors.lastname: Alvarado
authors.affiliation: INRA-UMR1318, Institut Jean-Pierre Bourgin, F-78026 Versailles, France.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Antelme
authors.affiliation: INRA-UR1268 Biopolymères, Interactions, Assemblages, F-44316 Nantes, France.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Bouchet
authors.affiliation: INRA-UMR1318, Institut Jean-Pierre Bourgin, F-78026 Versailles, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Cézard
authors.affiliation: INRA-UMR1318, Institut Jean-Pierre Bourgin, F-78026 Versailles, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Le Bris
authors.affiliation: INRA-UMR1318, Institut Jean-Pierre Bourgin, F-78026 Versailles, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Legée
authors.affiliation: INRA-UMR1318, Institut Jean-Pierre Bourgin, F-78026 Versailles, France.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Maia-Grondard
authors.affiliation: Laboratory of Tree Cell Biology, Division of Forest and Biomaterials Science, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
authors.forename: Arata
authors.initials: A
authors.lastname: Yoshinaga
authors.affiliation: INRA-UR1268 Biopolymères, Interactions, Assemblages, F-44316 Nantes, France.
authors.forename: Luc
authors.initials: L
authors.lastname: Saulnier
authors.affiliation: INRA-UR1268 Biopolymères, Interactions, Assemblages, F-44316 Nantes, France.
authors.forename: Fabienne
authors.initials: F
authors.lastname: Guillon
authors.affiliation: INRA-UMR1318, Institut Jean-Pierre Bourgin, F-78026 Versailles, France.
authors.forename: Richard
authors.initials: R
authors.lastname: Sibout
authors.affiliation: INRA-UMR1318, Institut Jean-Pierre Bourgin, F-78026 Versailles, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Lapierre
authors.affiliation: INRA-UR1268 Biopolymères, Interactions, Assemblages, F-44316 Nantes, France anne-laure.chateigner-boutin@nantes.inra.fr.
authors.forename: Anne-Laure
authors.initials: AL
authors.lastname: Chateigner-Boutin
mesh_terms: D056804:Biofuels / Q000032:analysis; D058431:Brachypodium / Q000235:genetics / Q000502:physiology*; D002473:Cell Wall / Q000737:chemistry; D002523:Edible Grain / Q000502:physiology; D008031:Lignin / Q000235:genetics* / Q000378:metabolism; D008780:Methyltransferases / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D010636:Phenols / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D018547:Plant Stems / Q000502:physiology
chemical_list: D056804:Biofuels; D010636:Phenols; D010940:Plant Proteins; C036909:lignocellulose; D008031:Lignin; D008780:Methyltransferases; C019608:caffeate O-methyltransferase
keywords: Brachypodium distachyon; COMT; ferulic acid; grains; lignins; para-coumaric acid; straw saccharification.