The Rapid Evolution of Resistance to Vip3Aa Insecticidal Protein in Mythimna separata (Walker) Is Not Related to Altered Binding to Midgut Receptors

Quan, Yudong; Yang, Jing; Wang, Yueqin; Hernández‐Martínez, Patricia; Ferré, Juan; He, Kanglai

doi:10.3390/toxins13050364

Cited by 13 publications

(11 citation statements)

References 40 publications

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“…As far as we know, this is the first study reporting detailed results from bioassays evaluating responses to Vip3Aa by field populations or laboratory strains of pink bollworm. Consistent with predictions based on the lack of shared midgut receptors between Vip and Cry toxins [14][15][16][17][18][19][20][21] and previous results from other lepidopterans, [22][23][24][25][26][27][28][29][30][31][32] the results here show strong crossresistance to Vip3Aa did not occur in strains of pink bollworm selected in the laboratory for > 700-fold resistance to Cry1Ac or to both Cry1Ac and Cry2Ab. Although the LC 50 of Vip3Aa was 3.5-fold lower for the Cry1Ac-resistant strain AZP-R than the Cry-susceptible laboratory strain APHIS-S, this does not provide clear evidence of negative cross-resistance because these strains are unrelated.…”

Section: Discussionsupporting

confidence: 92%

“…Both Vip3 and Cry toxins must bind specifically to midgut receptors to kill insects, 12,13 but strong cross‐resistance between them is not expected because they do not share midgut receptors 14–21 . Confirming this expectation, analysis of 48 pairwise comparisons between related strains of eight lepidopteran species found cross‐resistance was weak between Cry1 and Vip3 toxins and did not occur between Cry2 and Vip3 toxins 22 (also see the literature 23–32 ).…”

Section: Introductionmentioning

confidence: 91%

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Responses to Bt toxin Vip3Aa by pink bollworm larvae resistant or susceptible to Cry toxins

Tabashnik

Unnithan

Yelich

et al. 2022

Pest Management Science

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BACKGROUND: Transgenic crops that make insecticidal proteins from Bacillus thuringiensis (Bt) have revolutionized management of some pests. However, evolution of resistance to Bt toxins by pests diminishes the efficacy of Bt crops. Resistance to crystalline (Cry) Bt toxins has spurred adoption of crops genetically engineered to produce the Bt vegetative insecticidal protein Vip3Aa. Here we used laboratory diet bioassays to evaluate responses to Vip3Aa by pink bollworm (Pectinophora gossypiella), one of the world's most damaging pests of cotton.RESULTS: Against pink bollworm larvae susceptible to Cry toxins, Vip3Aa was less potent than Cry1Ac or Cry2Ab. Conversely, Vip3Aa was more potent than Cry1Ac or Cry2Ab against laboratory strains highly resistant to those Cry toxins. Five Crysusceptible field populations were less susceptible to Vip3Aa than a Cry-susceptible laboratory strain (APHIS-S). Relative to APHIS-S, significant resistance to Vip3Aa did not occur in strains selected in the laboratory for > 700-fold resistance to Cry1Ac or both Cry1Ac and Cry2Ab.CONCLUSIONS: Resistance to Cry1Ac and Cry2Ab did not cause strong cross-resistance to Vip3Aa in pink bollworm, which is consistent with predictions based on the lack of shared midgut receptors between these toxins and previous results from other lepidopterans. Comparison of the Bt toxin concentration in plants relative to the median lethal concentration (LC 50 ) from bioassays may be useful for estimating efficacy. The moderate potency of Vip3Aa against Cry1Ac-and Cry2Ab-resistant and susceptible pink bollworm larvae suggests that Bt cotton producing this toxin together with novel Cry toxins might be useful as one component of integrated pest management.

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Section: Discussionsupporting

confidence: 92%

Section: Introductionmentioning

confidence: 91%

Responses to Bt toxin Vip3Aa by pink bollworm larvae resistant or susceptible to Cry toxins

Tabashnik

Unnithan

Yelich

et al. 2022

Pest Management Science

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“…Finally, the mechanisms associated with Vip3A resistance will also need to be described. Recent data suggest that the mechanisms of insect resistance to Vip3A proteins are different from those described in insects that have evolved resistance to Cry proteins: it was reported that in some insects, such as Mythimna separata , the resistance to Vip3Aa is not related to altered binding to microvilli membranes ( 90 ). Furthermore, reduced expression of ALP in a Vip3-resistant strain of Heliothis virescens did not affect the binding of Vip3Aa to the microvilli membrane ( 91 ).…”

Section: Final Conclusionmentioning

confidence: 99%

Structural changes upon membrane insertion of the insecticidal pore-forming toxins produced by Bacillus thuringiensis

et al. 2023

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Different Bacillus thuringiensis (Bt) strains produce a broad variety of pore-forming toxins (PFTs) that show toxicity against insects and other invertebrates. Some of these insecticidal PFT proteins have been used successfully worldwide to control diverse insect crop pests. There are several studies focused on describing the mechanism of action of these toxins that have helped to improve their performance and to cope with the resistance evolved by different insects against some of these proteins. However, crucial information that is still missing is the structure of pores formed by some of these PFTs, such as the three-domain crystal (Cry) proteins, which are the most commercially used Bt toxins in the biological control of insect pests. In recent years, progress has been made on the identification of the structural changes that certain Bt insecticidal PFT proteins undergo upon membrane insertion. In this review, we describe the models that have been proposed for the membrane insertion of Cry toxins. We also review the recently published structures of the vegetative insecticidal proteins (Vips; e.g. Vip3) and the insecticidal toxin complex (Tc) in the membrane-inserted state. Although different Bt PFTs show different primary sequences, there are some similarities in the three-dimensional structures of Vips and Cry proteins. In addition, all PFTs described here must undergo major structural rearrangements to pass from a soluble form to a membrane-inserted state. It is proposed that, despite their structural differences, all PFTs undergo major structural rearrangements producing an extended α-helix, which plays a fundamental role in perforating their target membrane, resulting in the formation of the membrane pore required for their insecticidal activity.

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“…The resistance mechanisms of M. separata to Vip3Aa may be account for this result. Quan et al [34] reported that the resistance to Vip3Aa is not related to altered binding to midgut receptors, while altered binding to membrane receptors was the main mechanism of resistance to Cry proteins. Polygenic resistance against Cry1, Cry2 and Vip3Aa protein has also been reported in a number of insect species [25,35,36].…”

Section: Discussionmentioning

confidence: 99%

Inheritance and Fitness Costs of Vip3Aa19 Resistance in Mythimna separata

Wang

Yang

Zhang

et al. 2022

Toxins

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The “high-dose/refuge” strategy is expected to work most effectively when resistance is inherited as a functionally recessive trait and the fitness costs associated with resistance are present. In the present study, a laboratory selected Mythimna separata strain that have evolved >634.5-fold resistance to Vip3Aa19 was used to determine the mode of inheritance. To determine if fitness costs were associated with the resistance, life history parameters (larva stage, pupa stage, pupal weight, adult longevity and fecundity) of resistant (RR), -susceptible (SS) and heterozygous (R♂S♀ and R♀S♂) strains on nontoxic diet were assayed. The LC50 values of R♀S♂ were significantly higher than that of R♂S♀ (254.58 μg/g vs. 14.75 μg/g), suggesting that maternal effects or sex linkage were present. The effective dominance h of F1 offspring decreased as concentration increased, suggesting the resistance was functionally dominant at low concentration and recessive at high concentration. The analysis of observed and expected mortality of the progeny from a backcross suggested that more than one locus is involved in conferring Vip3Aa19 resistance. The results showed that significant differences in many life history traits were observed among the four insect genotypes. In short, resistance to Vip3Aa19 in M. separata was inherited as maternal and multigene and the resistance in the strain was associated with significant fitness costs. The results described here provide useful information for understanding resistance evolution and for developing resistance management strategies.

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The Rapid Evolution of Resistance to Vip3Aa Insecticidal Protein in Mythimna separata (Walker) Is Not Related to Altered Binding to Midgut Receptors

Cited by 13 publications

References 40 publications

Responses to Bt toxin Vip3Aa by pink bollworm larvae resistant or susceptible to Cry toxins

Responses to Bt toxin Vip3Aa by pink bollworm larvae resistant or susceptible to Cry toxins

Structural changes upon membrane insertion of the insecticidal pore-forming toxins produced by Bacillus thuringiensis

Inheritance and Fitness Costs of Vip3Aa19 Resistance in Mythimna separata

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