Also doing business as Dry Creek Laboratory, with relationship to the University of CA, Treetech Management Inc is working on new methods for controlling plant pests using transgenic plants. The methods control pests on a desired crop plant using transgenic pest trap plants of a different species or variety which are preferred host for the target pest, and thereby preferentially attract the pest. The pest trap plants comprise a gene encoding a protein toxic to the pest. Previously, Dry Creek researchers had worked on a gene known as GNA from the snowdrop (Galanthus nivalis). The gene makes a protein that repels nematodes and sap-sucking insects. Dry Creek licensed the gene from the British company that discovered it, Axis Genetics of Cambridge. Axis has successfully tested the gene in potatoes and tobacco. Nematodes are a type of microscopic worm. They stunt vine roots and infect them with viruses that wither the plant. One of most damaging is the fanleaf virus, which is spread by the dagger nematode (Xiphinema index). The only existing treatment for vines infected with nematodes is fumigation with methyl bromide, but this will be banned in the US in the year 2000. Sap-sucking insects, especially aphid-like phylloxera (Daktulosphaira vitifoliae), devastate grapevines in California's Central Valley and elsewhere. According to Dry Creek, there are no existing methods to control phylloxera, so the GNA gene might prove invaluable to wine growers. Dry Creek inserted the GNA gene into grapevine rootstock, rather than the fruit-bearing scions that are grafted onto it. One advantage of inserting genes only into the rootstock is that they will not find their way into the fruit. This should make them more acceptable to consumers. To insert the extra gene into vine embryos, the team used a standard gene shuttle called Agrobacterium tumefalens. The bacterium survives in the wild by inserting its own genetic material it into the roots of its plant hosts.
