Submitted to: Journal of Insect Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 29, 2004
Publication Date: N/A
Interpretive Summary: The development of resistance to Bt proteins in the European corn borer will affect the potential value of genetically-engineered Bt corn to corn producers. The research describes a new method to detect resistance to Bt proteins in the European corn borer. It is novel due to its use of corn tissue containing Bt protein instead of pure Bt protein placed into artificial diets. The method will not only benefit scientists researching the genetics of resistance management, but its use will provide data that will help regulatory agencies frame answers to resistance management decisions.
Technical Abstract: A method to use lyophilized corn tissue containing the Bacillus thuringiensis protein Cry1Ab is described for Ostrinia nubilalis (Lepidoptera: Crambidae). Tests were conducted on both laboratory and field-collected individuals to evaluate the bioassay for its potential use in artificial selection and resistance detection procedures. Freeze-drying of transgenic corn leaves did not decrease the amount of Cry1Ab present when compared to frozen leaf tissue collected from the same experimental rows. In addition, incorporating the tissue into an O. nubilalis meridic diet was effective in killing larvae. Analyses of F2 families originating from field-collected females indicated significant differences among families in the survival of F2 larvae on a diet composed of 5% of its nutritive material as Cry1Ab tissue. After backcrossing F2 individuals to a susceptible laboratory colony we observed that the survival of BCF2 families exposed to Cry1Ab tissue was dependent on the survival of the F2 from which they originated. The BCF2 family analysis indicates that the variation among F2 families for survival on Cry1Ab has a genetic component.