Bacillus thuringiensis serovar israelensis, an important agent for biological control of mosquitoes, carries many extrachromosomal elements. A linear molecule GIL01 and a circular plasmid pBtic235 correspond to bacteriophages that switch from the lysogenic to the lytic cycle in response to DNA damage. In this master's thesis, we used RNA sequencing to investigate the transcriptome dynamics during the induction of the lytic cycle of bacteriophage GIL01 and the effect on the pBtic235 plasmid. To this end, we developed a pipeline for reproducible and transparent analysis of RNA sequencing data. We detected an upregulation of host SOS response and genes involved in genome maintenance over time, peaking 30 minutes after induction. We observed a similar expression pattern for regulatory genes under the control of the P1 promoter on the GIL01 plasmid and genes on the pBtic235 plasmid. In addition, we detected time- and induction-independent expression of structural and lytic genes of the GIL01 plasmid, suggesting additional regulatory mechanisms. The transcriptional patterns on the GIL01 indicate two functional modules that likely correspond to individual transcripts. Overall, this work provides the first characterisation transcriptome dynamics in an important entomopathogenic strain B. thuringiensis carrying GIL01 and pBtic235 plasmids.
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