Previous Article | Next Article ![]()
Appl. Environ. Microbiol., May 1997, 1814-1819, Vol 63, No. 5
DJ Wright, M Iqbal, F Granero and J Ferre
A population (SERD3) of the diamondback moth (Plutella xylostella L.) with
field-evolved resistance to Bacillus thuringiensis subsp. kurstaki HD-1
(Dipel) and B. thuringiensis subsp. aizawai (Florbac) was collected.
Laboratory-based selection of two subpopulations of SERD3 with B.
thuringiensis subsp. kurstaki (Btk-Sel) or B. thuringiensis subsp. aizawai
(Bta-Sel) increased resistance to the selecting agent with little apparent
cross-resistance. This result suggested the presence of independent
resistance mechanisms. Reversal of resistance to B. thuringiensis subsp.
kurstaki and B. thuringiensis subsp. aizawai was observed in the unselected
SERD3 subpopulation. Binding to midgut brush border membrane vesicles was
examined for insecticidal crystal proteins specific to B. thuringiensis
subsp. kurstaki (Cry1Ac), B. thuringiensis subsp. aizawai (Cry1Ca), or both
(Cry1Aa and Cry1Ab). In the unselected SERD3 subpopulation (ca. 50- and
30-fold resistance to B. thuringiensis subsp. kurstaki and B. thuringiensis
subsp. aizawai), specific binding of Cry1Aa, Cry1Ac, and Cry1Ca was similar
to that for a susceptible population (ROTH), but binding of Cry1Ab was
minimal. The Btk-Sel (ca. 600-and 60-fold resistance to B. thuringiensis
subsp. kurstaki and B. thuringiensis subsp. aizawai) and Bta-Sel (ca.
80-and 300-fold resistance to B. thuringiensis subsp. kurstaki and B.
thuringiensis subsp. aizawai) subpopulations also showed reduced binding to
Cry1Ab. Binding of Cry1Ca was not affected in the Bta-Sel subpopulation.
The results suggest that reduced binding of Cry1Ab can partly explain
resistance to B. thuringiensis subsp. kurstaki and B. thuringiensis subsp.
aizawai. However, the binding of Cry1Aa, Cry1Ac, and Cry1Ca and the lack of
cross-resistance between the Btk-Sel and Bta-Sel subpopulations also
suggest that additional resistance mechanisms are present.
Copyright © 1997, American Society for Microbiology
A Change in a Single Midgut Receptor in the Diamondback Moth (Plutella xylostella) Is Only in Part Responsible for Field Resistance to Bacillus thuringiensis subsp. kurstaki and B. thuringiensis subsp. aizawai
Department of Biology, Imperial College of Science, Technology & Medicine, Silwood Park, Ascot, Berkshire SL5 7PY, United Kingdom, and Departament de Genetica, Facultat de Ciencies Biologiques, Universitat de Valencia, 46100 Burjassot, Valencia, Spain
This article has been cited by other articles:
| J. Bacteriol. | Microbiol. Mol. Biol. Rev. | Eukaryot. Cell | All ASM Journals |
|---|