Australia’s forest and wood product industry has an $18 billion turnover each year which depends on high quality timber, with strength a prime element. In a boost for the industry, Australian researchers have discovered a gene for wood strength in Eucalyptus trees.
The discovery means that saplings which have the gene can now be selected and grown on for higher quality timber. The discovery will help forest growers develop diagnostics for assessing which seedlings will produce higher quality timber.
The work was a collaborative effort between researchers at both the University of Melbourne and Ensis, CSIRO’s joint venture in forestry. This also included support from the South African forest products company Sappi. The discovery is published internationally in this month’s issue of The Plant Journal.
“Our findings present an important step towards the production of wood fibres with altered tensile strength, stiffness and elastic properties”, says Dr Antanas Spokevicius from the School of Forest and Ecosystem Science at the University of Melbourne.
Like other plants, trees have two cell wall layers, a thin primary wall which holds the contents of the cell, and a thick secondary wall which provides strength. In tree trunks and branches the secondary wall is crucial for supporting their immense height and weight, while at the same time providing the flexibility to allow them to withstand high winds.
The gene that is involved in wood strength determines how cellulose fibres (called microfibrils) are arranged in the second plant cell wall, much like steel cables add strength to concrete structures. By influencing the orientation of these microfibrils the gene confers different strength properties to the wood. The gene – called beta-tubulin - is part of the internal skeleton of the cell. Expression levels of the beta-tubulin gene were found to be critical in the orientation of cellulose microfibrils.
“These findings shed light on how trees have modified their cell walls to enable them to grow to great heights and thereby dominate terrestrial ecosystems” adds Dr Simon Southerton from CSIRO (Ensis) in Canberra.
The method used for studying the gene was also unique, as wood development is difficult to study and trees have such a long life cycle. The researchers studied the impact of the gene in small sectors of stem tissue directly in living trees and saw large changes in orientation of cellulose microfibrils.
“We demonstrate for the first time that this commercially important complex wood trait can be strongly influenced by a single gene” said Dr Gerd Bossinger from the School of Forest and Ecosystem Science, University of Melbourne.
Dr Antanas Spokevicius
School of Forest and Ecosystem Science
Faculty of Land and Food Resources
The University of Melbourne
Water Street, Creswick, Victoria, 3363
Phone: (03) 5321 4279 or 0439 822 359
Dr Simon Southerton
Ensis Genetics (CSIRO)
Banks St. Yarralumla ACT 2604
Phone: (02) 6281 8209 or 0413 001 614