Development Of Bio-Insecticides Based On Local Qatari Bacillus Thuringiensis Strains For The Biological Control Of Harmful Dipteran Disease Vectors

Abstract

The very friendly bacterium Bacillus thuringiensis (Bt) is the main source of environment-friendly and safe bioinsecticides used in the control of plant pests and animal and human disease vectors. A collection of 441 Qatari Bt strains were characterized and classified based on crystal morphology, plasmid patterns, crystal protein patterns and cry and cyt genes. In summary, the Bti strain QBT220 was recognized as the most efficient against Dipteran insects Aedes Aegypti. Two of its clones obtained by plasmid curing showed an increase of 115% in the -endotoxins. As example of novel Bt strains, QBT674 is a spherical crystal producing strain having cry2 gene but no cuboidal crystals. QBT555 is a Non-Bti strain with molecular profile very different from Bti strains, but expresses proteins like Cry11, Cry10 and Cyt1A. QBT229 showed high cytolytic activity due to five amino acid replacements in its β sheet that enhanced its anti-cancer activity.