Characterization of the pesticidal crystal toxin protein Cry11Aa from Bacillus thuringiensis serovar israelensis VCRC B646 for mosquito larvae control.

Effective mosquito control is essential for reducing the transmission of vector-borne diseases. This study focuses on the comprehensive characterization of mosquitocidal toxins produced by Bacillus thuringiensis serovar israelensis (Bti) VCRC B646 and the associated insecticidal genes. The bacterium was cultured, and the spore-crystal complex was purified to identify the mosquitocidal proteins. The mosquitocidal toxins produced by the isolate were evaluated against Aedes(Ae.) aegypti and Culex(Cx.) quinquefasciatus. SDS-PAGE and LC-MS were conducted to analyse the toxin, and PCR was performed to amplify the toxin gene. Toxicity bioassays indicated lethal concentrations (LC and LC) for Ae. aegypti (0.0022 mg/L and 0.004 mg/L), and Cx, quinquefasciatus (0.0025 mg/L and 0.0044 mg/L). SDS-PAGE and LC-MS analysis revealed that Cry11Aa5 (Pesticidal Crystal Protein) is the predominant toxin produced by this strain. PCR amplification confirmed the presence of genes encoding various insecticidal proteins, including Cry and Cyt toxins. Phylogenetic analysis was performed to assess the genetic relatedness and toxin profiles of the bacterial isolate. This detailed characterization of Bti VCRC B646 highlights its potential as a promising biopesticide candidate for mosquito control, contributing to the development of sustainable and eco-friendly strategies for vector management.