Caffeoyl coenzyme A O-methyltransferase down-regulation is associated with modifications in lignin and cell-wall architecture in flax secondary xylem.
Plant Physiol Biochem
; 47(1): 9-19, 2009 Jan.
Article
en En
| MEDLINE
| ID: mdl-19004632
ABSTRACT
Caffeoyl coenzyme A O-methyltransferase (CCoAOMT, EC 2.1.1.104) down-regulated-flax (Linum usitatissimum) plants were generated using an antisense strategy and functionally characterized. Chemical analyses (acetyl bromide and thioacidolysis) revealed that the lignin quantity was reduced and that the Syringyl/Guaïacyl (S/G) lignin monomer ratio was modified in the non-condensed lignin fraction of two independent down-regulated lines. These modifications were associated with altered xylem organization (both lines), reduced cell-wall thickness (one line) and the appearance of an irregular xylem (irx) phenotype (both lines). In addition UV microspectroscopy also indicated that CCoAOMT down-regulation induced changes in xylem cell-wall structure and the lignin fractions. Microscopic examination also suggested that CCoAOMT down-regulation could influence individual xylem cell size and identity. As a first step towards investigating the cellular mechanisms responsible for the unusual structure of flax lignin (G-rich, condensed), recombinant flax CCoAOMT protein was produced and its affinity for different potential substrates evaluated. Results indicated that the preferred substrate was caffeoyl coenzyme A, followed by 5-hydroxyconiferaldehyde suggesting that flax CCoAOMT possesses a small, but probably significant 5' methylating activity, in addition to a more usual 3' methylating activity.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Pared Celular
/
Lino
/
Xilema
/
Lignina
/
Metiltransferasas
Tipo de estudio:
Risk_factors_studies
Idioma:
En
Revista:
Plant Physiol Biochem
Asunto de la revista:
BIOQUIMICA
/
BOTANICA
Año:
2009
Tipo del documento:
Article
País de afiliación:
Francia