Overexpression of EgROP1, a Eucalyptus vascular-expressed Rac-like small GTPase, affects secondary xylem formation in Arabidopsis thaliana

Foucart Camille, Jauneau Alain, Gion Jean-Marc, Amelot Nicolas, Martinez Yves, Panegos Patricia, Grima Pettenati Jacqueline, Sivadon Pierre. 2009. Overexpression of EgROP1, a Eucalyptus vascular-expressed Rac-like small GTPase, affects secondary xylem formation in Arabidopsis thaliana. New Phytologist, 183 (4) : 1014-1029.

Quartile : Outlier, Sujet : PLANT SCIENCES

Résumé : To better understand the genetic control of secondary xylem formation in trees we analysed genes expressed during Eucalyptus xylem development. o Using eucalyptus xylem cDNA libraries, we identified EgROP1, a member of the plant ROP family of Rho-like GTPases. These signalling proteins are central regulators of many important processes in plants, but information on their role in xylogenesis is scarce. Quantitative real-time reverse-transcriptase polymerase chain reaction (qRT-PCR) confirmed that EgROP1 was preferentially expressed in the cambial zone and differentiating xylem in eucalyptus. Genetic mapping performed in a eucalyptus breeding population established a link between EgROP1 sequence polymorphisms and quantitative trait loci (QTLs) related to lignin profiles and fibre morphology. Overexpression of various forms of EgROP1 in Arabidopsis thaliana altered anisotropic cell growth in transgenic leaves, but most importantly affected vessel element and fibre growth in secondary xylem. Patches of fibre-like cells in the secondary xylem of transgenic plants showed changes in secondary cell wall thickness, lignin and xylan composition. These results suggest a role for EgROP1 in fibre cell morphology and secondary cell wall formation making it a good candidate gene for marker-based selection of eucalyptus trees.

Mots-clés Agrovoc : Eucalyptus, Arabidopsis thaliana, qualité, bois, lignification, fibre végétale, xylème, développement biologique, polymorphisme génétique, locus des caractères quantitatifs, expression des gènes, phylogénie, plante transgénique

Mots-clés complémentaires : QTL

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

• Foucart Camille, CNRS (FRA)
• Jauneau Alain, Institut fédératif de recherche FR40 "Signalisation cellulaire et biotechnologie végétale" (FRA)
• Gion Jean-Marc, CIRAD-BIOS-UPR Génétique forestière (FRA)
• Amelot Nicolas, CNRS (FRA)
• Martinez Yves, Institut fédératif de recherche FR40 "Signalisation cellulaire et biotechnologie végétale" (FRA)
• Panegos Patricia, CNRS (FRA)
• Grima Pettenati Jacqueline, CNRS (FRA)
• Sivadon Pierre, CNRS (FRA)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/569106/)

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