scholarly journals Cross-Resistance of Pink Bollworm (Pectinophora gossypiella) to Bacillus thuringiensis Toxins

2000 ◽  
Vol 66 (10) ◽  
pp. 4582-4584 ◽  
Author(s):  
Bruce E. Tabashnik ◽  
Yong-Biao Liu ◽  
Ruud A. de Maagd ◽  
Timothy J. Dennehy
Keyword(s):  
Bacillus Thuringiensis ◽  
Pink Bollworm ◽  
Pectinophora Gossypiella ◽  
Cross Resistance ◽  
Mechanism Of Resistance ◽  
Narrow Spectrum ◽  
Target Sites ◽  
The Cross

ABSTRACT Two strains of pink bollworm (Pectinophora gossypiella) selected in the laboratory for resistance to Bacillus thuringiensis toxin Cry1Ac had substantial cross-resistance to Cry1Aa and Cry1Ab but not to Cry1Bb, Cry1Ca, Cry1Da, Cry1Ea, Cry1Ja, Cry2Aa, Cry9Ca, H04, or H205. The narrow spectrum of resistance and the cross-resistance to activated toxin Cry1Ab suggest that reduced binding of toxin to midgut target sites could be an important mechanism of resistance.

scholarly journals Control of Resistant Pink Bollworm (Pectinophora gossypiella) by Transgenic Cotton That Produces Bacillus thuringiensis Toxin Cry2Ab

2002 ◽  
Vol 68 (8) ◽  
pp. 3790-3794 ◽  
Author(s):  
Bruce E. Tabashnik ◽  
Timothy J. Dennehy ◽  
Maria A. Sims ◽  
Karen Larkin ◽  
Graham P. Head ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
First Generation ◽  
Second Generation ◽  
Transgenic Cotton ◽  
Larval Survival ◽  
Genetically Engineered ◽  
Pink Bollworm ◽  
Pectinophora Gossypiella ◽  
Cross Resistance ◽  
Average Survival

ABSTRACT Crops genetically engineered to produce Bacillus thuringiensis toxins for insect control can reduce use of conventional insecticides, but insect resistance could limit the success of this technology. The first generation of transgenic cotton with B. thuringiensis produces a single toxin, Cry1Ac, that is highly effective against susceptible larvae of pink bollworm (Pectinophora gossypiella), a major cotton pest. To counter potential problems with resistance, second-generation transgenic cotton that produces B. thuringiensis toxin Cry2Ab alone or in combination with Cry1Ac has been developed. In greenhouse bioassays, a pink bollworm strain selected in the laboratory for resistance to Cry1Ac survived equally well on transgenic cotton with Cry1Ac and on cotton without Cry1Ac. In contrast, Cry1Ac-resistant pink bollworm had little or no survival on second-generation transgenic cotton with Cry2Ab alone or with Cry1Ac plus Cry2Ab. Artificial diet bioassays showed that resistance to Cry1Ac did not confer strong cross-resistance to Cry2Aa. Strains with >90% larval survival on diet with 10 μg of Cry1Ac per ml showed 0% survival on diet with 3.2 or 10 μg of Cry2Aa per ml. However, the average survival of larvae fed a diet with 1 μg of Cry2Aa per ml was higher for Cry1Ac-resistant strains (2 to 10%) than for susceptible strains (0%). If plants with Cry1Ac plus Cry2Ab are deployed while genes that confer resistance to each of these toxins are rare, and if the inheritance of resistance to both toxins is recessive, the efficacy of transgenic cotton might be greatly extended.

scholarly journals Asymmetrical cross-resistance between Bacillus thuringiensis toxins Cry1Ac and Cry2Ab in pink bollworm

2009 ◽  
Vol 106 (29) ◽  
pp. 11889-11894 ◽  
Author(s):  
B. E. Tabashnik ◽  
G. C. Unnithan ◽  
L. Masson ◽  
D. W. Crowder ◽  
X. Li ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Pink Bollworm ◽  
Cross Resistance

scholarly journals Mechanism of Resistance to Bacillus thuringiensis Toxin Cry1Ac in a Greenhouse Population of the Cabbage Looper, Trichoplusia ni

2006 ◽  
Vol 73 (4) ◽  
pp. 1199-1207 ◽  
Author(s):  
Ping Wang ◽  
Jian-Zhou Zhao ◽  
Ana Rodrigo-Sim�n ◽  
Wendy Kain ◽  
Alida F. Janmaat ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Binding Site ◽  
Trichoplusia Ni ◽  
Specific Binding ◽  
Laboratory Strain ◽  
Cabbage Looper ◽  
Cross Resistance ◽  
Resistance Pattern ◽  
Recessive Trait ◽  
Mechanism Of Resistance

ABSTRACT The cabbage looper, Trichoplusia ni, is one of only two insect species that have evolved resistance to Bacillus thuringiensis in agricultural situations. The trait of resistance to B. thuringiensis toxin Cry1Ac from a greenhouse-evolved resistant population of T. ni was introgressed into a highly inbred susceptible laboratory strain. The resulting introgression strain, GLEN-Cry1Ac-BCS, and its nearly isogenic susceptible strain were subjected to comparative genetic and biochemical studies to determine the mechanism of resistance. Results showed that midgut proteases, hemolymph melanization activity, and midgut esterase were not altered in the GLEN-Cry1Ac-BCS strain. The pattern of cross-resistance of the GLEN-Cry1Ac-BCS strain to 11 B. thuringiensis Cry toxins showed a correlation of the resistance with the Cry1Ab/Cry1Ac binding site in T. ni. This cross-resistance pattern is different from that found in a previously reported laboratory-selected Cry1Ab-resistant T. ni strain, evidently indicating that the greenhouse-evolved resistance involves a mechanism different from the laboratory-selected resistance. Determination of specific binding of B. thuringiensis toxins Cry1Ab and Cry1Ac to the midgut brush border membranes confirmed the loss of midgut binding to Cry1Ab and Cry1Ac in the resistant larvae. The loss of midgut binding to Cry1Ab/Cry1Ac is inherited as a recessive trait, which is consistent with the recessive inheritance of Cry1Ab/Cry1Ac resistance in this greenhouse-derived T. ni population. Therefore, it is concluded that the mechanism for the greenhouse-evolved Cry1Ac resistance in T. ni is an alteration affecting the binding of Cry1Ab and Cry1Ac to the Cry1Ab/Cry1Ac binding site in the midgut.

scholarly journals Cross-resistance and mechanism of resistance to Cry1Ab toxin from Bacillus thuringiensis in a field-derived strain of European corn borer, Ostrinia nubilalis

2011 ◽  
Vol 107 (3) ◽  
pp. 185-192 ◽  
Author(s):  
André L.B. Crespo ◽  
Ana Rodrigo-Simón ◽  
Herbert A.A. Siqueira ◽  
Eliseu J.G. Pereira ◽  
Juan Ferré ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Ostrinia Nubilalis ◽  
European Corn Borer ◽  
Cross Resistance ◽  
Corn Borer ◽  
Mechanism Of Resistance ◽  
Cry1ab Toxin

scholarly journals Cyt1A from Bacillus thuringiensis Lacks Toxicity to Susceptible and Resistant Larvae of Diamondback Moth (Plutella xylostella) and Pink Bollworm (Pectinophora gossypiella)

2001 ◽  
Vol 67 (1) ◽  
pp. 462-463 ◽  
Author(s):  
Susan K. Meyer ◽  
Bruce E. Tabashnik ◽  
Yong-Biao Liu ◽  
Margaret C. Wirth ◽  
Brian A. Federici
Keyword(s):  
Bacillus Thuringiensis ◽  
Plutella Xylostella ◽  
Diamondback Moth ◽  
Pink Bollworm ◽  
Pectinophora Gossypiella ◽  
Cry Toxins ◽  
Lepidopteran Pests ◽  
Lepidopteran Larvae

ABSTRACT We tested Cyt1Aa, a cytolytic endotoxin of Bacillus thuringiensis, against susceptible and Cry1A-resistant larvae of two lepidopteran pests, diamondback moth (Plutella xylostella) and pink bollworm (Pectinophora gossypiella). Unlike previous results obtained with mosquito and beetle larvae, Cyt1Aa alone or in combination with Cry toxins was not highly toxic to the lepidopteran larvae that we examined.

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