Programme Background

The cell walls of wood and fibre cells are made up of the two most abundant biopolymers on earth. One of these, lignin, is removed during pulping processes to yield fibre cells that are enriched in cellulose, the most abundant biopolymer on earth. Large amounts of hazardous chemicals and energy are required to remove lignin and refine the fibres used to manufacture paper products. The size, shape and chemical composition of wood and fibre cells also determine the strength and quality of the final product, paper. All of these properties are determined by the genes expressed during wood formation or xylogenesis. Many of these genes have been identified and extensively characterized, especially those involved in known biochemical pathways such as lignin and cellulose biosynthesis. However, the majority of genes and regulatory sequences that act in a concerted fashion to produce wood and fibre cells remain to be characterized in woody plants. The availability of the complete sequence of several plant genomes, including that of a forest tree (poplar), has generated powerful new approaches to identify wood and fibre genes. Not only are there now several new technologies available for high-throughput analysis of plant genes, but the model herbaceous plant, Arabidopsis thaliana, has been shown to produce secondary xylem (wood) if senescence is delayed. This means that this important model can be used to study the effect of genes isolated out of forest trees, and to test hypotheses regarding the function and potential use of these genes to modify wood and fibre properties.

 

Programme Description

The Wood and Fibre Molecular Genetics Programme is an exciting new research programme that started at the University of Pretoria in 2003. This collaborative effort with industrial forestry partners (Sappi Forests and Mondi Forests) is making use of high-throughout genomic technologies to identify and characterise genes and regulatory sequences involved in wood formation and fibre quality in fast-growing plantation forest trees. The programme is built on extensive experience gained in the genomic mapping of Eucalyptus tree species at North Carolina State University, and the excellent forestry research programmes of Sappi Forestry and Mondi Forestry. Specific research activities include: (a) the development of molecular tools for forest tree breeding, (b) gene discovery and functional analysis in model plants such as Arabidopsis, (c) high-throughput transcript profiling of gene expression in forest trees using microarray and cDNA-AFLP technology, and (d) characterization of allelic variation for wood and fibre genes in forest tree breeding programmes. Researchers and postgraduate students taking part in this programme have access to excellent facilities for high-throughput gene discovery research at the University of Pretoria. This includes two LI-COR DNA analysers, a microarray printer and scanner, sequencing facility, bioinformatics facility and new plant growth facilities housed in the FABI Square/Bioinformatics building.