Cry29A and Cry30A: two novel delta-endotoxins isolated from Bacillus thuringiensis serovar medellin

Area of Science:

• Microbiology
• Molecular Biology
• Entomology

Background:

• Bacillus thuringiensis (Bt) is a soil bacterium producing insecticidal crystal proteins.
• Mosquito control relies on effective and specific insecticides.
• Novel Bt toxins are sought for improved mosquito management.

Purpose of the Study:

• To clone and characterize two novel crystal protein genes from a mosquitocidal Bt strain.
• To evaluate the individual and synergistic toxicities of the novel proteins against key mosquito vectors.

Main Methods:

• Gene cloning and sequencing of novel crystal proteins from Bacillus thuringiensis serovar medellin.
• Individual toxicity assays of Cry29A and Cry30A against Aedes aegypti, Culex pipiens, and Anopheles stephensi.
• Synergistic toxicity assays combining Cry29A with Cry11Bb against Aedes aegypti.

Main Results:

• Two novel crystal protein genes, cry29A and cry30A, were successfully cloned and sequenced.
• Individual Cry29A and Cry30A proteins exhibited no significant toxicity against tested mosquito species.
• Cry29A demonstrated a four-fold synergistic effect on Cry11Bb toxicity in Aedes aegypti.

Conclusions:

• Novel Bt proteins Cry29A and Cry30A are not directly toxic to mosquitoes.
• Cry29A possesses synergistic potential, enhancing the efficacy of other Bt toxins like Cry11Bb.
• This finding opens avenues for developing more potent Bt-based mosquitocidal strategies.