Résumé
Mosquito control is often the main method used to reduce
mosquito-transmitted diseases. In order to investigate the genetic basis
of resistance to the bio-insecticide Bacillus thuringiensis subsp.
israelensis (Bti), we used information on polymorphism obtained from cDNA
tag sequences from pooled larvae of laboratory Bti-resistant and
susceptible Aedes aegypti mosquito strains to identify and analyse 1520
single nucleotide polymorphisms (SNPs). Of the 372 SNPs tested, 99.2% were
validated using DNA Illumina GoldenGate® array, with a strong correlation
between the allelic frequencies inferred from the pooled and individual
data (r = 0.85). A total of 11 genomic regions and five candidate genes
were detected using a genome scan approach. One of these candidate genes
showed significant departures from neutrality in the resistant strain at
sequence level. Six natural populations from Martinique Island were
sequenced for the 372 tested SNPs with a high transferability (87%), and
association mapping analyses detected 14 loci associated with Bti
resistance, including one located in a putative receptor for Cry11 toxins.
Three of these loci were also significantly differentiated between the
laboratory strains, suggesting that most of the genes associated with
resistance might differ between the two environments. It also suggests
that common selected regions might harbour key genes for Bti resistance.