Inheritance, fitness costs, incomplete resistance and feeding preferences in a laboratory-selected MON810-resistant strain of the true armyworm<i>Mythimna unipuncta</i>

García, Matías; Ortego, Félix; Hernández‐Crespo, Pedro; Farinós, Gema P.; Castañera, Pedro

doi:10.1002/ps.3971

Cited by 19 publications

(20 citation statements)

References 45 publications

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“…These results are consistent with nearly all previous results with Bt resistance, including resistance to Cry1Ab in Mythimna unipuncta [24], the ACB to Cry1Ab and Cry1Ac [10], H. armigera to Cry1Ac [25], O. nubilalis to Cry1Ab [26], greenhouse-derived strain of Trichoplusia ni to Cry1Ac, and B. thuringiensis subsp. Kurstaki [27,28].…”

Section: Discussionsupporting

confidence: 92%

Characterization of Asian Corn Borer Resistance to Bt Toxin Cry1Ie

Wang

Yang

Quan

et al. 2017

Toxins

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A strain of the Asian corn borer (ACB), Ostrinia furnacalis (Guenée), has evolved >800-fold resistance to Cry1Ie (ACB-IeR) after 49 generations of selection. The inheritance pattern of resistance to Cry1Ie in ACB-IeR strain and its cross-resistance to other Bt toxins were determined through bioassay by exposing neonates from genetic-crosses to toxins incorporated into the diet. The response of progenies from reciprocal F1 crosses were similar (LC50s: 76.07 vs. 74.32 μg/g), which suggested the resistance was autosomal. The effective dominance (h) decreased as concentration of Cry1Ie increased. h was nearly recessive or incompletely recessive on Cry1Ie maize leaf tissue (h = 0.02), but nearly dominant or incompletely dominant (h = 0.98) on Cry1Ie maize silk. Bioassay of the backcross suggested that the resistance was controlled by more than one locus. In addition, the resistant strain did not perform cross-resistance to Cry1Ab (0.8-fold), Cry1Ac (0.8-fold), Cry1F (0.9-fold), and Cry1Ah (1.0-fold). The present study not only offers the manifestation for resistance management, but also recommends that Cry1Ie will be an appropriate candidate for expression with Cry1Ab, Cry1Ac, Cry1F, or Cry1Ah for the development of Bt maize.

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Section: Discussionsupporting

confidence: 92%

Characterization of Asian Corn Borer Resistance to Bt Toxin Cry1Ie

Wang

Yang

Quan

et al. 2017

Toxins

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“…The high‐dose/refuge strategy has been successful in maintaining the susceptibility of agricultural insect pests to transgenic Bt crops with failures generally being linked to either a deviation from prescribed refuge sizes or the expression of an insufficient toxin dose by the transgenic plants (Tabashnik, Brévault & Carrière 2013; García et al . 2015). …”

Section: Introductionmentioning

confidence: 99%

“…Recent efforts to categorize and quantify fitness costs associated with field‐evolved resistance to Bt crops have reported variable results (Jakka, Knight & Jurat‐Fuentes 2014; Dangal & Huang 2015; García et al . 2015; Ingber & Gassmann 2015). …”

Section: Introductionmentioning

confidence: 99%

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Type of fitness cost influences the rate of evolution of resistance to transgenic Bt crops

Hackett

Bonsall

2016

Journal of Applied Ecology

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Summary The evolution of resistance to pesticides by insect pests is a significant challenge for sustainable agriculture. For transgenic crops expressing Bacillus thuringiensis (Bt), crystalline (Cry) toxins resistance evolution may be delayed by the high‐dose/refuge strategy in which a non‐toxic refuge is planted to promote the survival of susceptible insects. The high‐dose/refuge strategy may interact with fitness costs associated with resistance alleles to further delay resistance. However, while a diverse range of fitness costs are reported in the field, they are typically represented as a fixed reduction in survival or viability which is insensitive to ecological conditions such as competition. Furthermore, the potential dynamic consequences of restricting susceptible insects to a refuge which represents only a fraction of the available space have rarely been considered.We present a generalized discrete time model which utilizes dynamic programming methods to derive the optimal management decisions for the control of a theoretical insect pest population exposed to Bt crops. We consider three genotypes (susceptible homozygotes, resistant homozygotes and heterozygotes) and implement fitness costs of resistance to Bt toxins as either a decrease in the relative competitive ability of resistant insects or as a penalty on fecundity. Model analysis is repeated and contrasted for two types of density dependence: uniform density dependence which operates equally across the landscape and heterogeneous density dependence where the intensity of competition scales inversely with patch size and is determined separately for the refuge and Bt crop.When the planting of Bt is decided optimally, fitness costs to fecundity allow for the planting of larger areas of Bt crops than equivalent fitness costs that reduce the competitive ability of resistant insects.Heterogeneous competition only influenced model predictions when the proportional area of Bt planted in each season was decided optimally and resistance was not recessive. Synthesis and applications. The high‐dose/refuge strategy alone is insufficient to preserve susceptibility to transgenic Bacillus thuringiensis (Bt) crops in the long term when constraints upon the evolution of resistance are not insurmountable. Fitness costs may enhance the delaying effect of the refuge, but the extent to which they do so depends upon how the cost is realized biologically. Fitness costs which apply independently of other variables may be more beneficial to resistance management than costs which are only visible to selection under a limited range of ecological conditions.

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“…This shortfall in available data can be partly attributed to the success of the high-dose/refuge strategy; if instances of field-evolved resistance are rare, so studies of field-evolved resistance to Bt crops are similarly sparse. Recent efforts to categorize and quantify fitness costs associated with field-evolved resistance to Bt crops have reported variable results (Jakka, Knight & JuratFuentes 2014;Dangal & Huang 2015;Garc ıa et al 2015;Ingber & Gassmann 2015).…”

Section: Introductionmentioning

confidence: 99%

Type of fitness cost influences the rate of evolution of resistance to transgenic Bt crops

Hackett¹

2016

2016 International Congress of Entomology

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Summary1. The evolution of resistance to pesticides by insect pests is a significant challenge for sustainable agriculture. For transgenic crops expressing Bacillus thuringiensis (Bt), crystalline (Cry) toxins resistance evolution may be delayed by the high-dose/refuge strategy in which a non-toxic refuge is planted to promote the survival of susceptible insects. The high-dose/refuge strategy may interact with fitness costs associated with resistance alleles to further delay resistance. However, while a diverse range of fitness costs are reported in the field, they are typically represented as a fixed reduction in survival or viability which is insensitive to ecological conditions such as competition. Furthermore, the potential dynamic consequences of restricting susceptible insects to a refuge which represents only a fraction of the available space have rarely been considered. 2. We present a generalized discrete time model which utilizes dynamic programming methods to derive the optimal management decisions for the control of a theoretical insect pest population exposed to Bt crops. We consider three genotypes (susceptible homozygotes, resistant homozygotes and heterozygotes) and implement fitness costs of resistance to Bt toxins as either a decrease in the relative competitive ability of resistant insects or as a penalty on fecundity. Model analysis is repeated and contrasted for two types of density dependence: uniform density dependence which operates equally across the landscape and heterogeneous density dependence where the intensity of competition scales inversely with patch size and is determined separately for the refuge and Bt crop. 3. When the planting of Bt is decided optimally, fitness costs to fecundity allow for the planting of larger areas of Bt crops than equivalent fitness costs that reduce the competitive ability of resistant insects. 4. Heterogeneous competition only influenced model predictions when the proportional area of Bt planted in each season was decided optimally and resistance was not recessive. 5. Synthesis and applications. The high-dose/refuge strategy alone is insufficient to preserve susceptibility to transgenic Bacillus thuringiensis (Bt) crops in the long term when constraints upon the evolution of resistance are not insurmountable. Fitness costs may enhance the delaying effect of the refuge, but the extent to which they do so depends upon how the cost is realized biologically. Fitness costs which apply independently of other variables may be more beneficial to resistance management than costs which are only visible to selection under a limited range of ecological conditions.

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Inheritance, fitness costs, incomplete resistance and feeding preferences in a laboratory-selected MON810-resistant strain of the true armywormMythimna unipuncta

Cited by 19 publications

References 45 publications

Characterization of Asian Corn Borer Resistance to Bt Toxin Cry1Ie

Characterization of Asian Corn Borer Resistance to Bt Toxin Cry1Ie

Type of fitness cost influences the rate of evolution of resistance to transgenic Bt crops

Type of fitness cost influences the rate of evolution of resistance to transgenic Bt crops

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