Transposon-mediated resistance to Bacillus sphaericus in a field-evolved population of Culex pipiens (Diptera: Culicidae)
Article first published online: 29 MAR 2007
Volume 9, Issue 8, pages 2022–2029, August 2007
How to Cite
Darboux, I., Charles, J.-F., Pauchet, Y., Warot, S. and Pauron, D. (2007), Transposon-mediated resistance to Bacillus sphaericus in a field-evolved population of Culex pipiens (Diptera: Culicidae). Cellular Microbiology, 9: 2022–2029. doi: 10.1111/j.1462-5822.2007.00934.x
- Issue published online: 29 MAR 2007
- Article first published online: 29 MAR 2007
- Received 17 January, 2007; revised and accepted 26 February, 2007.
The binary toxin is the major active component of Bacillus sphaericus, a microbial larvicide used for controlling some vector mosquito-borne diseases. B. sphaericus resistance has been reported in many part of the world, leading to a growing concern for the usefulness of this environmental friendly insecticide. Here we characterize a novel mechanism of resistance to the binary toxin in a natural population of the West Nile virus vector, Culex pipiens. We show that the insertion of a transposable element-like DNA into the coding sequence of the midgut toxin receptor induces a new mRNA splicing event, unmasking cryptic donor and acceptor sites located in the host gene. The creation of the new intron causes the expression of an altered membrane protein, which is incapable of interacting with the toxin, thus providing the host mosquito with an advantageous phenotype. As a large portion of insect genomes is composed of transposable elements or transposable elements-related sequences, this new mechanism may be of general importance to appreciate their significance as potent agents for insect resistance to the microbial insecticides.