Author
Henneberry, Thomas | |
Jech, Lynn |
Submitted to: Arthropod Management Tests
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 6/1/2007 Publication Date: 10/1/2007 Citation: Henneberry, T.J., Jech, L.J. 2007. Effects of pink bollworm resistance to transgenic cotton on moth mating, oviposition and larval progeny development. Arthropod Management Tests Vol 32, Report No. M3. Interpretive Summary: Pink bollworm have been selected in the laboratory for resistance to transgenic cotton toxin incorporated in artificial diets. The insecticidal toxin is produced in cotton plants as a result of the genetically-engineered transfer of the toxin encoding gene from a bacterium. The resistance mechanism is related to the presence of a gene affecting binding of toxin to receptors in the insect’s midgut. We selected a pink bollworm strain for resistance to Bt cotton by feeding larvae for four days in each of 42 generations on cotton containing the insecticide toxin. The selected resistant strain does not appear to have the same mechanism of resistance as the pink bollworm strains selected by rearing larvae on toxic-fortified artificial diet. Technical Abstract: At least four strains of pink bollworm, Pectinophora gossypiella (Saunders), have been selected in the laboratory for resistance to insecticidal Cry1Ac toxin incorporated in artificial diets. The insecticidal toxin is produced in cotton plants as a result of the genetically-engineered transfer of the toxin encoding gene from the Bacillus thuringiensis (Bt) bacterium. The resistance mechanisms are related to the cadherin genotype in all the artificial diet strains selected. We selected a pink bollworm strain for resistance to Bt cotton by feeding larvae for four days in each of 42 generations on bolls of 'NuCOTN33B' containing the Cry1Ac toxin. The resistant strain, Bt4R, selected does not have the cadherin gene allele complex as do the pink bollworm strains selected by rearing larvae on Cry1Ac-fortified artificial diet. Some larvae of the Bt4R strain survive on diet containing the discriminating Cry1Ac diet dose for resistance, but none of the Bt4R larvae survived on cotton bolls. In contrast to strains selected on Cry1Ac diet, some survival of progeny of reciprocal moth crosses of Bt4R resistant and non-resistant strains occurred on the 10 ug/ml Cry1Ac-fortified diet. The combined results suggest a different pink bollworm mechanism of resistance to Bt toxin in cotton that may not be associated with the cadherin genotype. |