Document Type

Article

Publication Date

2007

Journal or Book Title

Journal of Economic Entomology

Volume

100

Issue

6

First Page

1862

Last Page

1870

DOI

10.1603/0022-0493(2007)100[1862:DONLAN]2.0.CO;2

Abstract

The survival of KS-SC DiPel-resistant and -susceptible European corn borer, Ostrinia nubilalis (Hübner), was evaluated on different tissues from corn, Zea mays L., hybrids, including a nontransgenic and two transgenic corn plants (events MON810 and Bt11) expressing high doses of Bacillus thuringiensis (Bt) Cry1Ab. The survival of Bt-resistant and -susceptible third instars was similar after a 5-d exposure to transgenic plant tissues. Survivors eventually died when returned to Bt corn tissues, but many were able to continue development when transferred to non-Bt corn tissues. Survival of resistant and susceptible larvae also was evaluated in bioassays with dilutions of leaf extracts from the three corn hybrids incorporated in an artificial diet. In these assays, survival was significantly higher for resistant O. nubilalis neonates at three of the five dilutions compared with the susceptible strain, but the resistance ratio was only 2.2- and 2.4-fold for MON810 and Bt11, respectively. The data demonstrate that Bt-resistant and unselected control O. nubilalis larvae were similar in susceptibility to MON810 and Bt11 event corn hybrids. Although we were unable to evaluate the Cry1Ab protein that larvae were exposed to in the transgenic tissue because of company restrictions, Cry1Ab protoxin produced in Escherichia coli was incubated with extracts from non-Bt corn leaves to simulate the in planta effect on the transgenic protein. Cry1Ab protoxin was hydrolyzed rapidly by enzymes in the corn extract into peptide fragments with molecular masses ranging from 132 to 74 kDa, and eventually 58 kDa. Overall, these data suggest that plant enzymes hydrolyze transgenic toxin to one that is functionally activated. Therefore, resistant insect populations with reduced proteinase activity do not seem to pose a threat to the efficacy of commercial MON810 and Bt11 corn hybrids.

Comments

This article is from Journal of Economic Entomology 100, no. 6 (2007): 1862–1870, doi:10.1603/0022-0493(2007)100[1862:DONLAN]2.0.CO;2.

Rights

This article is the copyright property of the Entomological Society of America and may not be used for any commercial or other private purpose without specific written permission of the Entomological Society of America.

Copyright Owner

Entomological Society of America

Language

en

File Format

application/pdf

Included in

Entomology Commons

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