Optimized cloning and expression workflow for Cry proteins from Bacillus wiedmannii biovar thuringiensis

Area of Science:

• Molecular Biology
• Microbial Biotechnology
• Insecticidal Protein Expression

Background:

• Efficient expression of insecticidal Cry proteins from Bacillus thuringiensis (Bt) is crucial for research.
• Bacillus wiedmannii biovar thuringiensis (Bwt) possesses multiple conserved cry genes, posing cloning challenges due to homologous flanking regions.

Purpose of the Study:

• To develop an optimized workflow for amplifying, cloning, and expressing Bwt cry genes.
• To enable structural and functional characterization of Bwt-derived Cry proteins.

Main Methods:

• Nested PCR for specific amplification of conserved cry genes.
• Cloning into the pSTAB vector using conventional methods or ligation-independent AQUA.
• Expression in the Bacillus thuringiensis subsp. israelensis 4Q7 acrystalliferous strain.
• Optimization of culture conditions for enhanced protein production.

Main Results:

• Successful amplification, cloning, and expression of cry4Ea1 and cry4Fa1 genes.
• Demonstrated efficiency of nested PCR and AQUA cloning for challenging sequences.
• Identified inoculum physiology and nutrient availability as key factors for Cry protein yield.

Conclusions:

• The optimized workflow enhances the molecular toolbox for Cry protein expression and characterization.
• Findings provide a foundation for improved biotechnological applications of insecticidal proteins.
• This study addresses limitations in heterologous expression of bacterial insecticidal toxins.