Transgenic Trees Closer to Reality
Crop and Soil Environmental News, September 1998
Extension Biotechnology Specialist
Scientists at Union Camp, Westvaco, and other paper companies are engineering sweet gum and cottonwood, among other trees, hoping to create a "supertree," one that grows faster than normal but retains hardiness. So far, this research has produced trees that have have rapid growth, but are delicate rather than hardy. These transgenic trees are tall, fast-growing specimens that require special treatments like fertilizing, pruning, and weed control to maintain rapid growth rates. Such trees are not desirable for commercial production because of the extra inputs needed, but does demonstrate the ability to genetically transform several types of trees.
Other scientists have had more success engineering trees to control weeds and insects that plague tree plantations. The Oregon State University Tree genetic Engineering Research Cooperative, a consortium of companies, government agencies, and universities, has engineered hybrid poplars to resist the herbicide glyphosate (Roundup) and produce insecticidal Bt toxins. Glyphosate, which is toxic to ordinary poplars, is not used in growing trees except to clear sites. However, with glyphosate-resistant trees, growers could spray plantations with glyphosate. This research program has also produced transgenic hybrid poplars to produce Bt toxin, in the hopes of controlling a serious leaf-eating pest, the cottonwood leaf beetle. The Cooperative so far has not applied for commercial permits for any of their engineered trees.
California and Swedish scientists are trying to speed up traditional tree breeding by transferring a gene that accelerates flower development from Arabidopsis into the European aspen. Arabiodopsis is a small, rapidly growing annual plant from the mustard family and is widely used as a model system in plant genetics research. Typically, an aspen is 10 to 20 years old before it produces flowers, which are essential for traditional breeding crosses. With the gene from Arabiodopsis, scientists hope to produce aspens that begin flowering at a much younger age.
While no permits for commercialization have been requested for transgenic trees, the above information demonstrates that several different types of transgenic trees have been developed and are currently in field trials. It is anticipated that the first transgenic trees will start appearing on the open market in 3 to 5 years.