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Mechanism of resistance to Bacillus thuringiensis toxin Cry1Ac in a greenhouse population of the cabbage looper, Trichoplusia ni.
Appl Environ Microbiol. 2007 Feb; 73(4):1199-207.AE

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.

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Authors+Show Affiliations

Wang P
Department of Entomology, Cornell University, Geneva, NY 14456, USA. pw15@cornell.edu
Zhao JZ
No affiliation info available
Rodrigo-Simón A
No affiliation info available
Kain W
No affiliation info available
Janmaat AF
No affiliation info available
Shelton AM
No affiliation info available
Ferré J
No affiliation info available
Myers J
No affiliation info available

MeSH

AnimalsBacillus thuringiensisBacillus thuringiensis ToxinsBacterial ProteinsBacterial ToxinsBrassicaDrug ResistanceEndotoxinsHemolysin ProteinsInsect ControlInsecticidesLepidoptera

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

17189446

Citation

Wang, Ping, et al. "Mechanism of Resistance to Bacillus Thuringiensis Toxin Cry1Ac in a Greenhouse Population of the Cabbage Looper, Trichoplusia Ni." Applied and Environmental Microbiology, vol. 73, no. 4, 2007, pp. 1199-207.
Wang P, Zhao JZ, Rodrigo-Simón A, et al. Mechanism of resistance to Bacillus thuringiensis toxin Cry1Ac in a greenhouse population of the cabbage looper, Trichoplusia ni. Appl Environ Microbiol. 2007;73(4):1199-207.
Wang, P., Zhao, J. Z., Rodrigo-Simón, A., Kain, W., Janmaat, A. F., Shelton, A. M., Ferré, J., & Myers, J. (2007). Mechanism of resistance to Bacillus thuringiensis toxin Cry1Ac in a greenhouse population of the cabbage looper, Trichoplusia ni. Applied and Environmental Microbiology, 73(4), 1199-207.
Wang P, et al. Mechanism of Resistance to Bacillus Thuringiensis Toxin Cry1Ac in a Greenhouse Population of the Cabbage Looper, Trichoplusia Ni. Appl Environ Microbiol. 2007;73(4):1199-207. PubMed PMID: 17189446.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Mechanism of resistance to Bacillus thuringiensis toxin Cry1Ac in a greenhouse population of the cabbage looper, Trichoplusia ni. AU - Wang,Ping, AU - Zhao,Jian-Zhou, AU - Rodrigo-Simón,Ana, AU - Kain,Wendy, AU - Janmaat,Alida F, AU - Shelton,Anthony M, AU - Ferré,Juan, AU - Myers,Judith, Y1 - 2006/12/22/ PY - 2006/12/26/pubmed PY - 2007/3/22/medline PY - 2006/12/26/entrez SP - 1199 EP - 207 JF - Applied and environmental microbiology JO - Appl Environ Microbiol VL - 73 IS - 4 N2 - 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. SN - 0099-2240 UR - https://www.unboundmedicine.com/medline/citation/17189446/Mechanism_of_resistance_to_Bacillus_thuringiensis_toxin_Cry1Ac_in_a_greenhouse_population_of_the_cabbage_looper_Trichoplusia_ni_ DB - PRIME DP - Unbound Medicine ER -