Tadao Asami

Strategy for Peroxidizing Herbicide-Resistant Crops

The widespread and persistent use of herbicides has increased the efficiency of modern crop production, and chemicals are now available for the control of most weeds in most crops. However, it is inevitable that there would be a biological result from dependence on a single control method. One result has been the selection and enrichment of genes which resulted in herbicide resistance in weed populations. A breakthrough in weed science was the finding of resistance to triazine herbicides (Ryan 1970), and the triazine-resistant weed biotypes then provided superb experimental materials for researchers. The dramatic progress in plant molecular biology made possible the isolation of the gene encoding D1 protein which is the target for triazine. Resistance was found to be due to the exchange of one or more amino acid (s) of the D1 protein. These findings led to the use of genetic engineering techniques in order to create herbicide-resistant crops. For example, a gene conferring resistance to glyphosate has been inserted into the genome of a number of crop species where it possesses glyphosate resistance (Dyer 1994). The resulting possible application of glyphosate to crops has received increasing attention and transgenic plants have been developed into commercial products.