Plant Genome III Conference Plant Genome III Conference
There is acute interest in applying genetic engineering techniques to forest trees, but there is little basic information to guide decisions about what genes to introduce to alter tree phenotype. Since forest trees are typically outbred, have long generation intervals, and/or possess an extremely large genome, they are not amenable to the "forward genetic" (mutant screen / positional cloning) analysis that has been so productive in Arabidopsis and other model systems. An adaptation of a "reverse genetic" approach would be to use antisense constructs to create single "mutations" in transgenic trees. Several groups have shown that function of individual genes involved in lignin polymerization can be impaired in trees via antisense manipulation. Antisense techniques could also be applied to genes involved in signal transduction pathways, since many of those genes affect processes of interest including the expression of numerous "downstream" genes. The success of the antisense approach in trees, as in animal and other plant systems, will depend on biological factors including pathway redundancy and gene product turnover, as well as the prior identification and cloning of genes involved in important signaling pathways. The antisense approach will be discussed in terms of defense signaling pathways.