Pectin methyl esterase inhibits intrusive and symplastic cell growth in developing wood cells of Populus

Siedlecka Anna, Wiklund Susanne, Péronne Marie-Amélie, Micheli Fabienne, Lesniewska Joanna, Sethson Ingmar, Edlund Ulf, Richard Luc, Sundberg Björn, Mellerowicz Ewa J.. 2008. Pectin methyl esterase inhibits intrusive and symplastic cell growth in developing wood cells of Populus. Plant Physiology, 146 (2) : 554-565.

Note générale : Wood cells, unlike most other cells in plants, grow by a unique combination of intrusive and symplastic growth. Fibers grow in diameter by diffuse symplastic growth, but they elongate solely by intrusive apical growth penetrating the pectin-rich middle lamella that cements neighboring cells together. In contrast, vessel elements grow in diameter by a combination of intrusive and symplastic growth. We demonstrate that an abundant pectin methyl esterase (PME; EC 3.1.1.11) from wood-forming tissues of hybrid aspen (Populus tremula x tremuloides) acts as a negative regulator of both symplastic and intrusive growth of developing wood cells. When PttPME1 expression was up- and down-regulated in transgenic aspen trees, the PME activity in wood-forming tissues was correspondingly altered. PME removes methyl ester groups from homogalacturonan (HG) and transgenic trees had modified HG methylesterification patterns, as demonstrated by two-dimensional nuclear magnetic resonance and immunostaining using PAM1 and LM7 antibodies. In situ distributions of PAM1 and LM7 epitopes revealed changes in pectin methylesterification in transgenic trees that were specifically localized in expanding wood cells. The results show that en block deesterification of HG by PttPME1 inhibits both symplastic growth and intrusive growth. PttPME1 is therefore involved in mechanisms determining fiber width and length in the wood of aspen trees. (Résumé d'auteur)

Mots-clés Agrovoc : Populus tremula, plante transgénique, expérimentation, bois, inhibiteur de croissance, croissance, pectinestérase, cellule

Classification Agris : F62 - Physiologie végétale - Croissance et développement
F30 - Génétique et amélioration des plantes
K10 - Production forestière

Champ stratégique Cirad : Axe 1 (2005-2013) - Intensification écologique

Auteurs et affiliations

• Siedlecka Anna, Swedish University of Agricultural Sciences (SWE)
• Wiklund Susanne, University of Umea (SWE)
• Péronne Marie-Amélie, Swedish University of Agricultural Sciences (SWE)
• Micheli Fabienne, CIRAD-BIOS-UMR DAP (BRA)
• Lesniewska Joanna, Swedish University of Agricultural Sciences (SWE)
• Sethson Ingmar, University of Umea (SWE)
• Edlund Ulf, University of Umea (SWE)
• Richard Luc, CNRS (FRA)
• Sundberg Björn, Swedish University of Agricultural Sciences (SWE)
• Mellerowicz Ewa J., Swedish University of Agricultural Sciences (SWE)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/543257/)

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