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Accueil du site > Equipes de recherche > Génomique fonctionnelle de l’Eucalyptus > Thèmes de recherche > Contrôle par l’environnement de la formation du bois > Involvement of CBF in the control of wood formation under cold conditions

Involvement of CBF in the control of wood formation under cold conditions

Among the 17 Eucalyptus CBF genes that we annotated, all were cold-induced in the stems some being preferentially expressed in phloem and others in xylem. Transgenic Eucalyptus lines overexpressing one CBF gene from E. gunnii [Navarro et al. 2009] exhibit an increased cold tolerance and reduced growth [Navarro et al. 2011]. Histochemistry revealed deep and broad changes in xylem structure of CBF overexpressors. Among the most spectacular, porosity (vessel area fraction) decreases, mainly due to a decrease in vessel diameter and occlusion of many vessels. With regard to fibers, density increases, associated to a smaller lumen area and increased cell wall proportion. Biochemical analyses showed a 2.6-fold increase in lignin content in the stems of overexpressors and as well as a significant increase of S/G unit ratio. RT-qPCR analysis indicated that except for 4CL (4-CoA Ligase), at least one gene of each family from phenylpropanoid pathway and lignin synthesis was up-regulated in the most modified lines. Several TFs possibly involved in the regulation of SCW synthesis were also up-regulated in the transgenic lines.