Aedes aegypti is an important vector of human diseases, such as dengue fever and yellow fever. Its control has been attempted by eliminating breeding sites, using predators, and with chemical insecticides. However, such control is still difficult because of operational limitations and the development of insect resistance. Therefore, Bacillus thuringiensis has been used for decades instead of physical and chemical control methods. B. thuringiensis israelensis is highly active against Ae aegypti. The high insecticidal activity and the low toxicity to other organisms have resulted in the rapid use of B. thuringiensis as an alternative method for control of mosquito populations. This bacterial strain produces a variety of toxins which collectively show high toxicity to Aedes aegypti. Presently, it has been assumed that all the three Cry toxins in this strain act via a common mechanism, while the Cyt toxin acts via an alternative mechanism. We recently showed that the Cry toxins also act via different mechanisms. To assess the mechanism of action of the Cry toxins, we developed mosquito lines that express dsRNA for Aedes Cad and other receptor genes under control of a heat shock promoter. Our data shows that while the cadherin gene is important for Cry11A toxicity, Cry4Aa and 4Ba toxicity is mediated by other receptor(s).

<i>Bacillus thuringiensis israelensis</i> toxins have multiple modes of action in <i>Aedes aegypti</i>

246th National Meeting (2013)

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Bacillus thuringiensis israelensis toxins have multiple modes of action in Aedes aegypti