Gene expression in Eucalyptus branch wood with marked variation in cellulose microfibril orientation and lacking G-layers
Article first published online: 14 APR 2008
© CSIRO (2008). Journal compilation © New Phytologist (2008)
Volume 179, Issue 1, pages 94–103, July 2008
How to Cite
Qiu, D., Wilson, I. W., Gan, S., Washusen, R., Moran, G. F. and Southerton, S. G. (2008), Gene expression in Eucalyptus branch wood with marked variation in cellulose microfibril orientation and lacking G-layers. New Phytologist, 179: 94–103. doi: 10.1111/j.1469-8137.2008.02439.x
- Issue published online: 14 APR 2008
- Article first published online: 14 APR 2008
- Received: 30 November 2007 Accepted: 7 February 2008
- cellulose microfibril angle;
- fasciclin-like AGP;
- tension wood
- • In response to gravitational stresses, angiosperm trees form tension wood in the upper sides of branches and leaning stems in which cellulose content is higher, microfibrils are typically aligned closely with the fibre axis and the fibres often have a thick inner gelatinous cell wall layer (G-layer).
- • Gene expression was studied in Eucalyptus nitens branches oriented at 45° using microarrays containing 4900 xylem cDNAs, and wood fibre characteristics revealed by X-ray diffraction, chemical and histochemical methods.
- • Xylem fibres in tension wood (upper branch) had a low microfibril angle, contained few fibres with G-layers and had higher cellulose and decreased Klason lignin compared with lower branch wood. Expression of two closely related fasciclin-like arabinogalactan proteins and a β-tubulin was inversely correlated with microfibril angle in upper and lower xylem from branches.
- • Structural and chemical modifications throughout the secondary cell walls of fibres sufficient to resist tension forces in branches can occur in the absence of G-layer enriched fibres and some important genes involved in responses to gravitational stress in eucalypt xylem are identified.