Mobile CRISPR-Cas9 based anti-phage system in E. coli

Area of Science:

• Microbiology
• Molecular Biology
• Biotechnology

Background:

• Escherichia coli is a vital microbial cell factory for industrial production.
• Bacteriophage infections pose a significant threat to E. coli's industrial applications.

Purpose of the Study:

• To develop and evaluate a mobile CRISPR-Cas9 based anti-phage system (MCBAS) for bacteriophage defense in E. coli.
• To assess the efficacy of two conjugative plasmids, pGM1 and pGM2, in preventing phage infection.

Main Methods:

• Designed two conjugative plasmids, pGM1 (one guide RNA) and pGM2 (two guide RNAs), for bacteriophage defense.
• Tested the plasmids against a filamentous phage infecting E. coli.
• Analyzed phage infection rates and performed sequence verification of phage genomes.

Main Results:

• Both pGM1 and pGM2 reduced phage infection rates in infected cells (1.6% and 0.2%, respectively).
• pGM2 significantly decreased phage infection rates to 0.1% in preventing infection, while pGM1 was less effective.
• Loss of defense function was linked to point mutations in phage genome sequences (protospacer or protospacer adjacent motif).

Conclusions:

• The mobile CRISPR-Cas9 based anti-phage system shows potential for protecting E. coli cell factories.
• The pGM2 plasmid demonstrates robust defense against filamentous phage infections.
• Understanding phage mutation mechanisms is crucial for sustained effectiveness of anti-phage systems.