Overexpression of EgROP1, a Eucalyptus vascular-expressed Rac-like small GTPase, affects secondary xylem formation in Arabidopsis thaliana
Article first published online: 22 JUN 2009
© The Authors (2009). Journal compilation © New Phytologist (2009)
Volume 183, Issue 4, pages 1014–1029, September 2009
How to Cite
Foucart, C., Jauneau, A., Gion, J.-M., Amelot, N., Martinez, Y., Panegos, P., Grima-Pettenati, J. and Sivadon, P. (2009), Overexpression of EgROP1, a Eucalyptus vascular-expressed Rac-like small GTPase, affects secondary xylem formation in Arabidopsis thaliana. New Phytologist, 183: 1014–1029. doi: 10.1111/j.1469-8137.2009.02910.x
- Issue published online: 10 AUG 2009
- Article first published online: 22 JUN 2009
- Received: 24 February 2009Accepted: 16 April 2009
- cell expansion;
- Rac-like ROP;
- secondary cell wall;
- secondary xylem;
- wood quality
- • To better understand the genetic control of secondary xylem formation in trees we analysed genes expressed during Eucalyptus xylem development.
- •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.