title: Characterization of a cinnamoyl-CoA reductase 1 (CCR1) mutant in maize: effects on lignification, fibre development, and global gene expression.
abstract: Cinnamoyl-CoA reductase (CCR), which catalyses the first committed step of the lignin-specific branch of monolignol biosynthesis, has been extensively characterized in dicot species, but few data are available in monocots. By screening a Mu insertional mutant collection in maize, a mutant in the CCR1 gene was isolated named Zmccr1(-). In this mutant, CCR1 gene expression is reduced to 31% of the residual wild-type level. Zmccr1(-) exhibited enhanced digestibility without compromising plant growth and development. Lignin analysis revealed a slight decrease in lignin content and significant changes in lignin structure. p-Hydroxyphenyl units were strongly decreased and the syringyl/guaiacyl ratio was slightly increased. At the cellular level, alterations in lignin deposition were mainly observed in the walls of the sclerenchymatic fibre cells surrounding the vascular bundles. These cell walls showed little to no staining with phloroglucinol. These histochemical changes were accompanied by an increase in sclerenchyma surface area and an alteration in cell shape. In keeping with this cell type-specific phenotype, transcriptomics performed at an early stage of plant development revealed the down-regulation of genes specifically associated with fibre wall formation. To the present authors' knowledge, this is the first functional characterization of CCR1 in a grass species.
authors.affiliation: Laboratoire de Recherche en Sciences Végétales, Pôle de Biotechnologies Végétales, Castanet Tolosan, France.
authors.forename: Barek
authors.initials: B
authors.lastname: Tamasloukht
authors.forename: Mary Sarah-Jane
authors.initials: MS
authors.lastname: Wong Quai Lam
authors.forename: Yves
authors.initials: Y
authors.lastname: Martinez
authors.forename: Koffi
authors.initials: K
authors.lastname: Tozo
authors.forename: Odile
authors.initials: O
authors.lastname: Barbier
authors.forename: Cyril
authors.initials: C
authors.lastname: Jourda
authors.forename: Alain
authors.initials: A
authors.lastname: Jauneau
authors.forename: Gisèle
authors.initials: G
authors.lastname: Borderies
authors.forename: Sandrine
authors.initials: S
authors.lastname: Balzergue
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Renou
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Huguet
authors.forename: Jean Pierre
authors.initials: JP
authors.lastname: Martinant
authors.forename: Christophe
authors.initials: C
authors.lastname: Tatout
authors.forename: Catherine
authors.initials: C
authors.lastname: Lapierre
authors.forename: Yves
authors.initials: Y
authors.lastname: Barrière
authors.forename: Deborah
authors.initials: D
authors.lastname: Goffner
authors.forename: Magalie
authors.initials: M
authors.lastname: Pichon
mesh_terms: D000445:Aldehyde Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D002473:Cell Wall / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D018506:Gene Expression Regulation, Plant; D007150:Immunohistochemistry; D008031:Lignin / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D010802:Phylogeny; D010940:Plant Proteins / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D003313:Zea mays / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D008031:Lignin; D000445:Aldehyde Oxidoreductases; C019904:cinnamoyl CoA reductase