LAUSR

The mosquito Aedes aegypti is associated with the spread of many viral diseases in humans, including Dengue virus (DENVs), Yellow fever virus (YFV), Zika virus (ZIKV), and Chikungunya virus (CHIKV). Bacillus thuringiensis (Bt) is widely used as biopesticide, which produces Cry toxins for mosquito control. The Cry toxins bind mainly to important receptors, including alkaline phosphatase (ALP) and aminopeptidase-N (APN). This work investigated the function of a C-type lectin, CTLGA9, in A. aegypti in response to Cry toxins. Our results showed that CTLTGA9 protein interacted with brush border membrane vesicles (BBMVs) of A. aegypti larvae, and with ALP1, APN and Cry11Aa proteins by Far-Western blot and ELISA methods. Furthermore, molecular docking showed overlapping binding sites in ALP1 and APN for binding to Cry11Aa and CTLGA9. The toxicity assays further demonstrated that CTLGA9 inhibited the larvicidal activity of Cry toxins.Based on the results of molecular docking, CTLGA9 may compete with Cry11Aa for binding to ALP1 and APN receptors, and thus decreases the mosquitocidal toxicity of Cry11Aa. Our results provide further insights into better understanding the mechanism of Cry toxin and help improve the Cry toxicity for mosquito control.