O-022. Genetic Improvement of Bacillus thuringiensis subsp. aegypti for Industrial Production of the Biopesticide: AGERIN®

Y. A. O. Ellazeik;
Mansoura Univ., Mansoura, EGYPT.

Bacillus thuringiensis subsp. aegypti is a broad spectrum strain isolated from pink bollworm cadavers, Mansoura District, Egypt. The strain is patented in the USA and Egypt, and is currently used to produce the first Egyptian biopesticide: AGERIN®. However, the strain turned to be highly sensitive to phage infection, especially during large-scale fermentation which limited its production and causes great economic loss. Moreover, chemical sun screeners, such as ρ-amino benzoic acid (PABA), are being added to the final product to protect it from degradation by sun rays, which limit its use on crops, vegetables and fruits being exported to European market. Genetic improvements of the strain to produce its own melanin pigment and resist phage infection were the objectives of this project. Repeated use of UV as mutagenic agent resulted in three melanin-producing mutants and one phage resistant/tolerant mutant. These mutants were characterized at both the bacteriological and molecular levels to confirm their belonging to the B. thruingiensis. The ability of the mutants to produce melanin and/or resist phage infection was as important as its ability to produce the insecticidal crystal proteins (ICP). PCR was used to confirm the integrity of the genes encoding for ICPs and bioassays against cotton leaf worm was used to measure the insecticidal potentials of the resultant mutants. Mutants withstand the challenges with specific phages and exposure to the direct sunlight at its peak for two hours. Trials for cloning the genes encoding for phage resistance and melanin production were done and are being evaluated.