Insecticidal mechanisms mediated by CRY4BA and CRY11AA binding proteins of Asian tiger mosquito

The Asian tiger mosquito (Aedes albopictus) is a mosquito species native to Southeast Asia that has now spread across Türkiye. Given its vector potential and remarkable ability to colonize various environmental conditions, Ae. albopictus is considered one of the most significant invasive mosquito species globally. Under experimental conditions, this mosquito species has demonstrated the potential to transmit four dengue serotypes, yellow fever, chikungunya, Ross River virus, and at least 22 other arboviruses. Consequently, preventing the spread of invasive mosquitoes necessitates the use of environmentally friendly pesticides that are species-specific and have minimal impact on non-target organisms. In this study, we aimed to investigate the larvicidal effects of Cry4Ba and Cry11Aa toxins, which are among the most effective biopesticides for targeting Aedes species. Furthermore, we sought to identify the receptors for Cry4Ba and Cry11Aa toxins to elucidate their mechanisms of action in Ae. albopictus. Despite the critical role of toxin-receptor interactions in Cry toxin efficacy, the receptors that interact with Cry toxins in Ae. albopictus have not yet been characterized. Our findings revealed that two alkaline phosphatases, a vacuolar-type ATPase subunit B, and a maltase-like receptor serve as functional receptors for Cry4Ba and Cry11Aa in Ae. albopictus larvae. Additionally, we demonstrated that the susceptibility of mosquito larvae to Cry toxins is influenced by the downregulation of these receptor gene expressions using RNA interference. These results provide new insights into the mechanisms of Cry toxin action and may contribute to developing more effective mosquito management strategies.