Table 2
INSECT RESISTANCE GENES TRANSFERRED TO CROP
SPECIES
| alpha-Amylase inhibitors | Lectins |
| Bean | Snowdrop lectin—GNA |
| Cereal | Pea lectin |
| Protease inhibitors | Wheat germ agglutinin—WGA |
| Soybean (serine protease) | Jacalin |
| Barley (trypsin) | Rice lectin |
| Squash (trypsin) | Others |
| Cowpea (trypsin) | Bean chitinase |
| Mustard (serine protease) | Tobacco peroxidase |
| Rice (cysteine protease) | Tomato chitinase |
| Potato (protease inhibitors I and II) | Tryptophan decarboxylase |
| Soybean (Kunitz trypsin inhibitor) | Animal genes |
| Tomato (protease inhibitors I and II) | Various enzyme inhibitors |
Taken from Schuler et al TIBTECH 16 168-175 (1998).
8.4 Industrial crops: managing the risk of chemical entry to
the food chain
The focus of debate on GM crops has been safety in respect
to food use and the consequences for the environment. Relatively
little attention has been paid to broader questions of risk analysis
and management. Programmes designed to detect gene transfer to
non-transgenic crops and related species and the spread of resistance
to the Btk toxin amongst target insects are underway. However
we consider the impact of new GM crops grown for industrial rather
than food/feed purposes is likely to become of great importance.
Plants have long been used as bioreactors able to produce high
value naturally-occurring chemicals, predominately for pharmaceutical
or cosmetic use. Recombinant technology has greatly expanded the
options for the production of high-value products, particularly
peptide and protein based therapeutics. Transgenic constructs
exist which are able to express antibodies, to produce proteins
for vaccines and various signalling peptides. At the other end
of the scale, low-cost bulk feedstock can also be produced economically
and will be able to replace, in part, feedstock derived from non-renewable
sources. Bulk production has focused on the use of oilseed rape
in which the oil produced has been modified by changing the expression
of key enzymes. One of the first GM plants to be approved for
release in the USA (1993) was an oilseed rape modified to produce
high concentrations of lauric acid for use in the detergent industry.
Table 3 shows this and some other transgenic rape crops designed
for industrial purposes which have reached the stage of field
trials.
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