The bacteriophage (phage) GIL01 infects the bacteria Bacillus thuringiensis serovar israelensis. A distinct characteristic of isolates of this bacterium is the fact that they produce larvicidal crystal toxins during sporulation. Commercial products based on different B. thuringiensis isolates are the most used biopesticides in the world. Most isolates of B. thuringiensis serovar israelensis already possess the genome of the phage (prophage) GIL01. Phage GIL01 is a temperate phage, that switches to a lytic cycle, when bacterial DNA damage occurs. In our studies we used the isolate B. thuringiensis serovar israelensis T0131, which was isolated from soil in Brazil. In contrast to most isolates of B. thuringiensis serovar israelensis, T0131 does not include the prophage GIL01. During our study we were able to produce a lysogenic strain T0131-GIL01. This enabled us to investigate whether the presence of GIL01 in T0131 effects the survivability of Galleria mellonella larvae, or the larvae of Drosophila suzukii. Using the methods of forced feeding and subcutaneous injection of bacterial spores, we were not able to determine whether the presence of GIL01 in T0131 effects the survivability of G. mellonella larvae. Forced feeding with pure GIL01 however, significantly increased the survival rate of G. mellonella. By adding spores of T0131 and T0131 with GIL01 in a lysogenic cycle to the growth medium, we determined that none of the tested strains effects the survivability or development time of D. suzukii from egg to adult fly.
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