Global regulators enable bacterial adaptation to a phenotypic trade-off

Area of Science:

• Microbiology
• Evolutionary Biology
• Genetics

Background:

• Cellular fitness relies on balancing multiple phenotypes like growth and motility.
• Coordinated growth and motility are crucial for microbial colonization and cancer.
• Bacteria use local and global regulators to control these phenotypes, but their evolutionary interaction is unclear.

Purpose of the Study:

• To investigate how CRISPR-mediated knockdowns of global and local transcription factors affect growth and motility in Escherichia coli.
• To understand the interplay between local and global regulation during evolutionary adaptation.
• To elucidate the role of pleiotropic regulators in adapting multiple phenotypes.

Main Methods:

• Utilized CRISPR interference (CRISPRi) for targeted gene knockdown in Escherichia coli.
• Assessed impacts on bacterial growth and motility across three distinct environments.
• Employed computational simulations to model evolutionary trajectories.

Main Results:

• Local regulators primarily influenced motility.
• Global regulators jointly modulated both growth and motility.
• Simulations suggested local regulators are modified before global regulators during adaptation.

Conclusions:

• Local regulators are important for initial motility adjustments.
• Global regulators play a key role in balancing growth and motility trade-offs.
• Pleiotropic regulators are central to the multi-phenotypic adaptation process in bacteria.