Selection and characterization of resistance to the Vip3Aa20 protein from <i>Bacillus thuringiensis</i> in <i>Spodoptera frugiperda</i>

Vip3A proteins are widely used for controlling pest Lepidoptera. Different binding sites with different receptors in the insect midgut membrane and lack of cross‐resistance with crystal (Cry) proteins enhance their applicability, as both single proteins and proteins pyramided with Cry proteins in transgenic Bt crops. Vip3A proteins are effective but there is relatively little information about their structure, function, activation, specificity, and mode of action. In addition, the mechanism of insect resistance to these proteins is unknown. Phylogenetic analysis and multiple sequence alignment showed that Vip3A proteins are genetically distant from Cry proteins. The mode of action and insecticidal activity of Vip3A proteins are discussed in this review. This review also provides detailed information about the Vip3A protein family that may aid in the design of more efficient pest management strategies in response to insect resistance to insecticidal proteins. © 2020 Society of Chemical Industry

Section: Resistance and Cross Resistancementioning

confidence: 99%

Bacillus thuringiensis vegetative insecticidal protein family Vip3A and mode of action against pest Lepidoptera

Chakrabarty

Jin

et al. 2020

“…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 . 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 . As reported in the literature, at the beginning of the resistance evolution the main carriers of the resistance allele are the heterozygous individuals, which behave phenotypically as susceptible individuals when offered Bt maize leaves …”

Section: Discussionmentioning

confidence: 93%

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

Amaral

Guidolin

Salmeron

et al. 2019

Self Cite

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

“…In a previous study, Bernardi et al . characterized resistance to Vip3A in a Brazilian population of S. frugiperda .…”

Section: Discussionmentioning

confidence: 99%

“…However, it is critical to point out that these preliminary results on fitness costs were just based on comparison of a laboratory susceptible strain. A critical factor in evaluating fitness costs associated with resistance is to ensure the similar genetic background between the compared strains to eliminate any modifier genes that could affect the relative fitness . Therefore, further research with a near‐isogenic Vip3A‐resistant strain is needed to clarify the fitness costs associated with the Vip3A resistance in S. frugiperda .…”

Section: Discussionmentioning

confidence: 99%

F₂ screen, inheritance and cross‐resistance of field‐derived Vip3A resistance in Spodoptera frugiperda (Lepidoptera: Noctuidae) collected from Louisiana, USA

Yang

Morsello

Head

et al. 2018