scholarly journals Mannose Phosphate Isomerase Isoenzymes in Plutella xylostella Support Common Genetic Bases of Resistance toBacillus thuringiensis Toxins in Lepidopteran Species

2001 ◽  
Vol 67 (2) ◽  
pp. 979-981 ◽  
Author(s):  
Salvador Herrero ◽  
Juan Ferré ◽  
Baltasar Escriche
Keyword(s):  
Bacillus Thuringiensis ◽  
Plutella Xylostella ◽  
Strong Correlation ◽  
Heliothis Virescens ◽  
Cross Resistance ◽  
Lepidopteran Species ◽  
Biochemical Genetic ◽  
Two Populations ◽  
Genetic Bases

ABSTRACT A strong correlation between two mannose phosphate isomerase (MPI) isoenzymes and resistance to Cry1A toxins from Bacillus thuringiensis has been found in a Plutella xylostellapopulation. MPI linkage to Cry1A resistance had previously been reported for a Heliothis virescens population. The fact that the two populations share similar biochemical, genetic, and cross-resistance profiles of resistance suggests the occurrence of homologous resistance loci in both species.

scholarly journals Common Receptor for Bacillus thuringiensis Toxins Cry1Ac, Cry1Fa, and Cry1Ja in Helicoverpa armigera, Helicoverpa zea, and Spodoptera exigua

2005 ◽  
Vol 71 (9) ◽  
pp. 5627-5629 ◽  
Author(s):  
Carmen Sara Hernández ◽  
Juan Ferré
Keyword(s):  
Bacillus Thuringiensis ◽  
Helicoverpa Armigera ◽  
Helicoverpa Zea ◽  
Spodoptera Exigua ◽  
Cross Resistance ◽  
Binding Studies ◽  
Lepidopteran Species ◽  
Common Receptor ◽  
Binding Data ◽  
Helicoverpa Armígera

ABSTRACT Binding studies using 125I-Cry1Ac and biotinylated Cry1Fa toxins indicate the occurrence of a common receptor for Cry1Ac, Cry1Fa, and Cry1Ja in Helicoverpa armigera, Helicoverpa zea, and Spodoptera exigua. Our results, along with previous binding data and the observed cases of cross-resistance, suggest that this pattern seems to be widespread among lepidopteran species.

scholarly journals Bacillus thuringiensis Vip3Aa Toxin Resistance in Heliothis virescens (Lepidoptera: Noctuidae)

2017 ◽  
Vol 83 (9) ◽  
Author(s):  
Brian R. Pickett ◽  
Asim Gulzar ◽  
Juan Ferré ◽  
Denis J. Wright
Keyword(s):  
Bacillus Thuringiensis ◽  
Heliothis Virescens ◽  
Insect Pests ◽  
Management Strategies ◽  
Resistance Management ◽  
Cross Resistance ◽  
Inheritance Of Resistance ◽  
Resistant Parent ◽  
Bt Crops ◽  
Content Type

ABSTRACT Laboratory selection with Vip3Aa of a field-derived population of Heliothis virescens produced >2,040-fold resistance in 12 generations of selection. The Vip3Aa-selected (Vip-Sel)-resistant population showed little cross-resistance to Cry1Ab and no cross-resistance to Cry1Ac. Resistance was unstable after 15 generations without exposure to the toxin. F1 reciprocal crosses between Vip3Aa-unselected (Vip-Unsel) and Vip-Sel insects indicated a strong paternal influence on the inheritance of resistance. Resistance ranged from almost completely recessive (mean degree of dominance [h] = 0.04 if the resistant parent was female) to incompletely dominant (mean h = 0.53 if the resistant parent was male). Results from bioassays on the offspring from backcrosses of the F1 progeny with Vip-Sel insects indicated that resistance was due to more than one locus. The results described in this article provide useful information for the insecticide resistance management strategies designed to overcome the evolution of resistance to Vip3Aa in insect pests. IMPORTANCE Heliothis virescens is an important pest that has the ability to feed on many plant species. The extensive use of Bacillus thuringiensis (Bt) crops or spray has already led to the evolution of insect resistance in the field for some species of Lepidoptera and Coleoptera. The development of resistance in insect pests is the main threat to Bt crops. The effective resistance management strategies are very important to prolong the life of Bt plants. Lab selection is the key step to test the assumption and predictions of management strategies prior to field evaluation. Resistant insects offer useful information to determine the inheritance of resistance and the frequency of resistance alleles and to study the mechanism of resistance to insecticides.

scholarly journals Common, but Complex, Mode of Resistance of Plutella xylostella to Bacillus thuringiensis Toxins Cry1Ab and Cry1Ac

2005 ◽  
Vol 71 (11) ◽  
pp. 6863-6869 ◽  
Author(s):  
Ali H. Sayyed ◽  
Roxani Gatsi ◽  
M. Sales Ibiza-Palacios ◽  
Baltasar Escriche ◽  
Denis J. Wright ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Resistance Genes ◽  
Plutella Xylostella ◽  
Specific Binding ◽  
Management Strategies ◽  
Cross Resistance ◽  
Single Pair ◽  
Dominant Trait ◽  
Binding Studies ◽  
Susceptible Population

ABSTRACT A field collected population of Plutella xylostella (SERD4) was selected in the laboratory with Bacillus thuringiensis endotoxins Cry1Ac (Cry1Ac-SEL) and Cry1Ab (Cry1Ab-SEL). Both subpopulations showed similar phenotypes: high resistance to the Cry1A toxins and little cross-resistance to Cry1Ca or Cry1D. A previous analysis of the Cry1Ac-SEL showed incompletely dominant resistance to Cry1Ac with more than one factor, at least one of which was sex influenced. In the present study reciprocal mass crosses between Cry1Ab-SEL and a laboratory susceptible population (ROTH) provided evidence that Cry1Ab resistance was also inherited as incompletely dominant trait with more than one factor, and at least one of the factors was sex influenced. Analysis of single pair mating indicated that Cry1Ab-SEL was still heterogeneous for Cry1Ab resistance genes, showing genes with different degrees of dominance. Binding studies showed a large reduction of specific binding of Cry1Ab and Cry1Ac to midgut membrane vesicles of the Cry1Ab-SEL subpopulation. Cry1Ab-SEL was found to be more susceptible to trypsin-activated Cry1Ab toxin than protoxin, although no defect in toxin activation was found. Present and previous results indicate a common basis of resistance to both Cry1Ab and Cry1Ac in selected subpopulations and suggest that a similar set of resistance genes are responsible for resistance to Cry1Ab and Cry1Ac and are selected whichever toxin was used. The possibility of an incompletely dominant trait of resistant to these toxins should be taken into account when considering refuge resistance management strategies.

scholarly journals Dual Resistance to Bacillus thuringiensis Cry1Ac and Cry2Aa Toxins in Heliothis virescens Suggests Multiple Mechanisms of Resistance

2003 ◽  
Vol 69 (10) ◽  
pp. 5898-5906 ◽  
Author(s):  
Juan Luis Jurat-Fuentes ◽  
Fred L. Gould ◽  
Michael J. Adang
Keyword(s):  
Bacillus Thuringiensis ◽  
Brush Border ◽  
Heliothis Virescens ◽  
Brush Border Membrane ◽  
Membrane Vesicles ◽  
Cross Resistance ◽  
Gene Stacking ◽  
Mechanisms Of Resistance ◽  
Toxin Binding ◽  
Evolution Of Resistance

ABSTRACT One strategy for delaying evolution of resistance to Bacillus thuringiensis crystal (Cry) endotoxins is the production of multiple Cry toxins in each transgenic plant (gene stacking). This strategy relies upon the assumption that simultaneous evolution of resistance to toxins that have different modes of action will be difficult for insect pests. In B. thuringiensis-transgenic (Bt) cotton, production of both Cry1Ac and Cry2Ab has been proposed to delay resistance of Heliothis virescens (tobacco budworm). After previous laboratory selection with Cry1Ac, H. virescens strains CXC and KCBhyb developed high levels of cross-resistance not only to toxins similar to Cry1Ac but also to Cry2Aa. We studied the role of toxin binding alteration in resistance and cross-resistance with the CXC and KCBhyb strains. In toxin binding experiments, Cry1A and Cry2Aa toxins bound to brush border membrane vesicles from CXC, but binding of Cry1Aa was reduced for the KCBhyb strain compared to susceptible insects. Since Cry1Aa and Cry2Aa do not share binding proteins in H. virescens, our results suggest occurrence of at least two mechanisms of resistance in KCBhyb insects, one of them related to reduction of Cry1Aa toxin binding. Cry1Ac bound irreversibly to brush border membrane vesicles (BBMV) from YDK, CXC, and KCBhyb larvae, suggesting that Cry1Ac insertion was unaffected. These results highlight the genetic potential of H. virescens to become resistant to distinct Cry toxins simultaneously and may question the effectiveness of gene stacking in delaying evolution of resistance.

scholarly journals Cross-Resistance and Stability of Resistance to Bacillus thuringiensis Toxin Cry1C in Diamondback Moth

2001 ◽  
Vol 67 (7) ◽  
pp. 3216-3219 ◽  
Author(s):  
Yong-Biao Liu ◽  
Bruce E. Tabashnik ◽  
Susan K. Meyer ◽  
Neil Crickmore
Keyword(s):  
Bacillus Thuringiensis ◽  
Plutella Xylostella ◽  
Resistant Strain ◽  
Diamondback Moth ◽  
Field Population ◽  
Cross Resistance ◽  
Bacillus Thuringiensis Toxin ◽  
Stability Of Resistance ◽  
Resistant Strains ◽  
Reported Data

ABSTRACT We tested toxins of Bacillus thuringiensis against larvae from susceptible, Cry1C-resistant, and Cry1A-resistant strains of diamondback moth (Plutella xylostella). The Cry1C-resistant strain, which was derived from a field population that had evolved resistance to B. thuringiensis subsp.kurstaki and B. thuringiensis subsp.aizawai, was selected repeatedly with Cry1C in the laboratory. The Cry1C-resistant strain had strong cross-resistance to Cry1Ab, Cry1Ac, and Cry1F, low to moderate cross-resistance to Cry1Aa and Cry9Ca, and no cross-resistance to Cry1Bb, Cry1Ja, and Cry2A. Resistance to Cry1C declined when selection was relaxed. Together with previously reported data, the new data on the cross-resistance of a Cry1C-resistant strain reported here suggest that resistance to Cry1A and Cry1C toxins confers little or no cross-resistance to Cry1Bb, Cry2Aa, or Cry9Ca. Therefore, these toxins might be useful in rotations or combinations with Cry1A and Cry1C toxins. Cry9Ca was much more potent than Cry1Bb or Cry2Aa and thus might be especially useful against diamondback moth.

scholarly journals Genetic and Biochemical Approach for Characterization of Resistance to Bacillus thuringiensis Toxin Cry1Ac in a Field Population of the Diamondback Moth, Plutella xylostella

2000 ◽  
Vol 66 (4) ◽  
pp. 1509-1516 ◽  
Author(s):  
Ali H. Sayyed ◽  
Robert Haward ◽  
Salvador Herrero ◽  
Juan Ferré ◽  
Denis J. Wright
Keyword(s):  
Bacillus Thuringiensis ◽  
Plutella Xylostella ◽  
Diamondback Moth ◽  
Resistance Mechanism ◽  
Membrane Vesicles ◽  
Cross Resistance ◽  
Binding Studies ◽  
Susceptible Population ◽  
Biochemical Approach

ABSTRACT Four subpopulations of a Plutella xylostella (L.) strain from Malaysia (F4 to F8) were selected with Bacillus thuringiensis subsp.kurstaki HD-1, Bacillus thuringiensis subsp. aizawai, Cry1Ab, and Cry1Ac, respectively, while a fifth subpopulation was left as unselected (UNSEL-MEL). Bioassays at F9 found that selection with Cry1Ac, Cry1Ab, B. thuringiensissubsp. kurstaki, and B. thuringiensis subsp. aizawai gave resistance ratios of >95, 10, 7, and 3, respectively, compared with UNSEL-MEL (>10,500, 500, >100, and 26, respectively, compared with a susceptible population, ROTH). Resistance to Cry1Ac, Cry1Ab, B. thuringiensis subsp. kurstaki, andB. thuringiensis subsp. aizawai in UNSEL-MEL declined significantly by F9. The Cry1Ac-selected population showed very little cross-resistance to Cry1Ab, B. thuringiensis subsp. kurstaki, andB. thuringiensis subsp. aizawai(5-, 1-, and 4-fold compared with UNSEL-MEL), whereas the Cry1Ab-,B. thuringiensis subsp. kurstaki-, and B. thuringiensis subsp.aizawai-selected populations showed high cross-resistance to Cry1Ac (60-, 100-, and 70-fold). The Cry1Ac-selected population was reselected (F9 to F13) to give a resistance ratio of >2,400 compared with UNSEL-MEL. Binding studies with125I-labeled Cry1Ab and Cry1Ac revealed complete lack of binding to brush border membrane vesicles prepared from Cry1Ac-selected larvae (F15). Binding was also reduced, although less drastically, in the revertant population, which indicates that a modification in the common binding site of these two toxins was involved in the resistance mechanism in the original population. Reciprocal genetic crosses between Cry1Ac-reselected and ROTH insects indicated that resistance was autosomal and showed incomplete dominance. At the highest dose of Cry1Ac tested, resistance was recessive while at the lowest dose it was almost completely dominant. The F2 progeny from a backcross of F1 progeny with ROTH was tested with a concentration of Cry1Ac which would kill 100% of ROTH moths. Eight of the 12 families tested had 60 to 90% mortality, which indicated that more than one allele on separate loci was responsible for resistance to Cry1Ac.

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