9317885 Fogleman/Mcintyre Cytochrome P450 genes produce enzymes that allow insects to tolerate poisonous chemicals such as insecticides and certain plant compounds. Some plants protect themselves from insects (and other herbivores) by making chemical compounds that are toxic in the animals which try to feed on them. Cytochrome P450 enzymes detoxify chemical compounds, usually by changing their chemical structure. The study of P450 genes, therefore, will provide information as to how insects become resistant to insecticides and/or plant defensive chemicals. %%% This proposal involves the use of an insect plant model system. The insects are fruit flies of the genus Drosophila, and the plants are columnar cacti which grow in the Sonoran Desert of Southwestern United States and Mexico. A wealth of background information on this model system has already been obtained including data on the ecology and genetics of the fruit flies and identification and characterization of the toxic chemicals that the cacti produce. Employing modern techniques of molecular genetics, the experiments included in this proposal will investigate how P450 genes evolve and how they are regulated. A better understanding of the mechanisms by which insects evolve P450 mediated resistance and by which P450 resistance genes are genetically regulated would represent a major advancement in the areas of insect ecological genetics and evolution.
