Please use this identifier to cite or link to this item: https://www.arca.fiocruz.br/handle/icict/27501
Title: Detection of an allele conferring resistance to Bacillus sphaericus binary toxin in Culex quinquefasciatus populations by molecular screening
Authors: Chalegre, Karlos Diogo de Melo
Romão, Tatiany Patrícia
Amorim, Liliane Barbosa
Anastacio, Daniela Bandeira
Barros, Rosineide Arruda de
Oliveira, Cláudia Maria Fontes de
Regis, Lêda
Melo Neto, Osvaldo Pompílio de
Silva Filha, Maria Helena Neves Lobo
Affilliation: Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Entomologia. Recife, PE, Brasil.
Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Entomologia. Recife, PE, Brasil.
Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Entomologia. Recife, PE, Brasil.
Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Entomologia. Recife, PE, Brasil.
Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Entomologia. Recife, PE, Brasil.
Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Entomologia. Recife, PE, Brasil.
Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Entomologia. Recife, PE, Brasil.
Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Microbiologia. Recife, PE, Brasil.
Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Entomologia. Recife, PE, Brasil.
Abstract: The activity of the Bacillus sphaericus binary (Bin) toxin on Culex quinquefasciatus larvae depends on its specific binding to the Cqm1 receptor, a midgut membrane-bound alpha-glucosidase. A 19-nucleotide deletion in the cqm1 gene (cqm1(REC)) mediates high-level resistance to Bin toxin. Here, resistance in nontreated and B. sphaericus-treated field populations of C. quinquefasciatus was assessed through bioassays as well as a specific PCR assay designed to detect the cqm1(REC) allele in individual larvae. Resistance ratios at 90% lethal concentration, gathered through bioassays, were close to 1 and indicate that the selected populations had similar levels of susceptibility to B. sphaericus, comparable to that of a laboratory colony. A diagnostic PCR assay detected the cqm1(REC) allele in all populations investigated, and its frequency in two nontreated areas was 0.006 and 0.003, while the frequency in the B. sphaericus-treated population was significantly higher. Values of 0.053 and 0.055 were detected for two distinct sets of samples, and homozygote resistant larvae were found. Evaluation of Cqm1 expression in individual larvae through alpha-glucosidase assays corroborated the allelic frequency revealed by PCR. The data from this study indicate that the cqm1(REC) allele was present at a detectable frequency in nontreated populations, while the higher frequency in samples from the treated area is, perhaps, correlated with the exposure to B. sphaericus. This is the first report of the molecular detection of a biolarvicide resistance allele in mosquito populations, and it confirms that the PCR-based approach is suitable to track such alleles in target populations.
Keywords: Culex quinquefasciatus
PCR
Alleles
keywords: Culex quinquefasciatus
PCR
Alelos
DeCS: Alelos
Animais
Toxinas bacterianas / toxicidade
Culex / efeitos de drogas
Culex / genética
Resistência a droga
Freqüência Genética
Genes, Inseto
Homozigoto
Imunidade Inata
Proteínas de Insetos / genética
Proteínas de Insetos / metabolismo
Reação em Cadeia da Polimerase / métodos
Supressão de Seqüência
alfa-glucosidases / genética
alfa-glucosidases / metabolismo
Issue Date: 2009
Citation: CHALEGRE, K. D. DE M. et al. Detection of an allele conferring resistance to Bacillus sphaericus binary toxin in Culex quinquefasciatus populations by molecular screening. Applied and Environmental Microbiology, v. 75, n. 4, p. 1044–1049, fev. 2009.
DOI: 10.1128/AEM.02032-08
ISSN: 1098-5336
Copyright: open access
Appears in Collections:PE - IAM - Artigos de Periódicos

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