title: Functional analyses of cellulose synthase genes in flax (Linum usitatissimum) by virus-induced gene silencing.
abstract: Flax (Linum usitatissimum) bast fibres are located in the stem cortex where they play an important role in mechanical support. They contain high amounts of cellulose and so are used for linen textiles and in the composite industry. In this study, we screened the annotated flax genome and identified 14 distinct cellulose synthase (CESA) genes using orthologous sequences previously identified. Transcriptomics of 'primary cell wall' and 'secondary cell wall' flax CESA genes showed that some were preferentially expressed in different organs and stem tissues providing clues as to their biological role(s) in planta. The development for the first time in flax of a virus-induced gene silencing (VIGS) approach was used to functionally evaluate the biological role of different CESA genes in stem tissues. Quantification of transcript accumulation showed that in many cases, silencing not only affected targeted CESA clades, but also had an impact on other CESA genes. Whatever the targeted clade, inactivation by VIGS affected plant growth. In contrast, only clade 1- and clade 6-targeted plants showed modifications in outer-stem tissue organization and secondary cell wall formation. In these plants, bast fibre number and structure were severely impacted, suggesting that the targeted genes may play an important role in the establishment of the fibre cell wall. Our results provide new fundamental information about cellulose biosynthesis in flax that should facilitate future plant improvement/engineering.
authors: UMR INRA 1281 Stress Abiotiques et Différenciation des Végétaux Cultivés, Université Lille Nord de France Lille 1, Villeneuve d'Ascq, France.
authors: Maxime
authors: M
authors: Chantreau
authors: INRA, UMR 614 Fractionnement des AgroRessources et Environnement, Reims, France.|UMR 614 Fractionnement des AgroRessources et Environnement, Université de Reims Champagne-Ardenne, Reims, France.
authors: Brigitte
authors: B
authors: Chabbert
authors: UMR CNRS 8198 Laboratoire de Génétique & Evolution des Populations Végétales, Université Lille Nord de France Lille 1, Villeneuve d'Ascq, France.
authors: Sylvain
authors: S
authors: Billiard
authors: UMR INRA 1281 Stress Abiotiques et Différenciation des Végétaux Cultivés, Université Lille Nord de France Lille 1, Villeneuve d'Ascq, France.
authors: Simon
authors: S
authors: Hawkins
authors: UMR INRA 1281 Stress Abiotiques et Différenciation des Végétaux Cultivés, Université Lille Nord de France Lille 1, Villeneuve d'Ascq, France.
authors: Godfrey
authors: G
authors: Neutelings
mesh_terms: D002874:Chromosome Mapping; D019597:Flax / Q000201:enzymology / Q000235:genetics*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D020868:Gene Silencing; D017343:Genes, Plant / Q000235:genetics* / Q000502:physiology; D005964:Glucosyltransferases / Q000235:genetics*; D010802:Phylogeny; D018547:Plant Stems / Q000378:metabolism
chemical_list: D005964:Glucosyltransferases; C478648:cellulose synthase
keywords: cellulose; fibres; flax; gene expression; silencing; virus-induced gene silencing