Evaluating transgenic plants for suitability in pest and resistance management programs

Caprio, Michael A.; Sumerford, Douglas V.

doi:10.1007/978-1-4020-5933-9_38

Cited by 11 publications

(9 citation statements)

References 60 publications

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“…Susceptible survival in the 25-fold dilution tissue bioassay was 76.8%, while heterozygous survival in the Cry1F leaf bioassay was 8.3% for the same hybrid and maize stage. Clearly, given that larvae did not have 99% mortality at a 25-fold dilution of leaf tissue, larvae would likewise not have 99% mortality on a 50-fold dilution, so neither the USEPA 15 nor the Caprio et al 9 Pest Manag Sci 2016; 72: 974-979 operational definition for high dose was met. Using the 25-fold dilution concept, the Cry1Ac soybean events TIC107 and MON 87701 × MON 89788 were apparently high dose for Anticarsia gemmatalis Hübner, but were not high dose for Pseudoplusia includens (Walker).…”

Section: Discussionmentioning

confidence: 99%

“…6,8 For Bt plants, the higher the Cry protein concentration, the lower is the fitness advantage of heterozygotes in relation to homozygous susceptible. 9 Studies with models have shown that high dose is expected to be more effective in delaying resistance than low dose. 5,7 Field experience with Bt crops generally supports this expectation.…”

Section: Introductionmentioning

confidence: 99%

“…15 According to this concept, if the Bt plant produces 25-fold the Bt concentration necessary to kill more than 99% of all susceptible insects, then D WT ≈ 0 and resistance is presumed to be recessive. 12 Later, Caprio et al 9 reviewed more extensive literature and suggested that a better operational definition is that the Bt plant must produce 50-fold the Bt concentration to kill more than 99% of all susceptible insects; however, this definition has rarely been used. One of the most common ways to test these operational definitions is to dilute Bt plant tissue 25-fold (or 50-fold) and determine whether the diluted tissue kills more than 99% of susceptible larvae.…”

Section: Introductionmentioning

confidence: 99%

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Dominance of Cry1F resistance in Spodoptera frugiperda (Lepidoptera: Noctuidae) on TC1507Bt maize in Brazil

Farias

Andow

Horikoshi

et al. 2015

Pest Management Science

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Resistance to Cry1F in TC1507 maize is incompletely recessive in S. frugiperda. TC1507 maize is not high dose for S. frugiperda. Additional or alternative resistance management strategies, such as the replacement of single-trait Bt maize with pyramided Bt maize, which produces multiple proteins targeting the same insect pests, should be implemented wherever this technology is in use and S. frugiperda is the major pest.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dominance of Cry1F resistance in Spodoptera frugiperda (Lepidoptera: Noctuidae) on TC1507Bt maize in Brazil

Farias

Andow

Horikoshi

et al. 2015

Pest Management Science

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“…The EPA-SAP (1998) has suggested that 25 times the concentration of toxin at which 99% of the individuals in a susceptible population die [lethal concentration 99 (LC 99 )] may function as a high dose. Caprio et al (2000) argued that 50 times the LC 99 is better supported by the published data on insecticide resistance. These standards can be readily operationalized for transgenic Bt crops, but they may contribute a false sense of security about the validity of the high-dose assumption.…”

Section: R E S I S T a N C E R I S K A N D M A N A G E M E N Tmentioning

confidence: 99%

Assessing environmental risks of transgenic plants

Andow¹,

Zwahlen²

2005

Ecology Letters

278

216

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By the end of the 1980s, a broad consensus had developed that there were potential environmental risks of transgenic plants requiring assessment and that this assessment must be done on a case-by-case basis, taking into account the transgene, recipient organism, intended environment of release, and the frequency and scale of the intended introduction. Since 1990, there have been gradual but substantial changes in the environmental risk assessment process. In this review, we focus on changes in the assessment of risks associated with non-target species and biodiversity, gene flow, and the evolution of resistance. Non-target risk assessment now focuses on risks of transgenic plants to the intended local environment of release. Measurements of gene flow indicate that it occurs at higher rates than believed in the early 1990s, mathematical theory is beginning to clarify expectations of risks associated with gene flow, and management methods are being developed to reduce gene flow and possibly mitigate its effects. Insect pest resistance risks are now managed using a high-dose/refuge or a refuge-only strategy, and the present research focuses on monitoring for resistance and encouraging compliance to requirements. We synthesize previous models for tiering risk assessment and propose a general model for tiering. Future transgenic crops are likely to pose greater challenges for risk assessment, and meeting these challenges will be crucial in developing a scientifically coherent risk assessment framework. Scientific understanding of the factors affecting environmental risk is still nascent, and environmental scientists need to help improve environmental risk assessment.

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“…We assign this result to a low frequency of homozygous individuals for the resistance allele in the field populations and the high dose of the Vip3Aa20 protein expressed by the Bt maize leaf for S. frugiperda. 20,26 Resistance is recessive for the resistance allele detected in Brazil; thus, only homozygous individuals for this allele are able to survive when fed maize leaves expressing Vip3Aa20. 10 As reported in the literature, at the beginning of the resistance evolution the main carriers of the resistance allele are the heterozygous individuals, 27 which behave phenotypically as susceptible individuals when offered Bt maize leaves.…”

Section: Discussionmentioning

confidence: 99%

Geographical distribution of Vip3Aa20 resistance allele frequencies in Spodoptera frugiperda (Lepidoptera: Noctuidae) populations in Brazil

Amaral

Guidolin

Salmeron

et al. 2019

Pest Management Science

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BACKGROUND The use of Bt plants has been the main strategy for controlling the fall armyworm Spodoptera frugiperda (J. E. Smith) in Brazil. However, many resistance cases were already registered. The resistance of S. frugiperda to the Vip3Aa20 protein was recently characterized under laboratory conditions but it is still efficient under field conditions. Here, resistance monitoring studies were conducted using phenotypic (purified protein and Bt maize leaves) and genotypic (F1 and F2 screen) methods to support insect resistance management (IRM) programs and preserve Vip3Aa20 technology on maize. RESULTS Phenotypic monitoring with purified protein showed two populations significantly different from the susceptible strain on the second crop season in 2016. This number increased for the first and second crop seasons in 2017 in several regions. The genotypic monitoring estimated a mean frequency of the resistance allele of 0.0027 for the F1 screen and 0.0033 for the F2 screen. Three new resistant strains to Vip3Aa20 were selected from F2 screen assays. Complementation tests on these new resistant strains were positive with the previous resistant strain. CONCLUSION Here we showed that the resistance allele of S. frugiperda to Vip3Aa20 protein is widely distributed in maize‐producing regions in Brazil and its frequency increases throughout crop seasons. © 2019 Society of Chemical Industry

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Evaluating transgenic plants for suitability in pest and resistance management programs

Cited by 11 publications

References 60 publications

Dominance of Cry1F resistance in Spodoptera frugiperda (Lepidoptera: Noctuidae) on TC1507Bt maize in Brazil

Dominance of Cry1F resistance in Spodoptera frugiperda (Lepidoptera: Noctuidae) on TC1507Bt maize in Brazil

Assessing environmental risks of transgenic plants

Geographical distribution of Vip3Aa20 resistance allele frequencies in Spodoptera frugiperda (Lepidoptera: Noctuidae) populations in Brazil

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