Engineering RGB color vision into Escherichia coli

Area of Science:

• Synthetic Biology
• Microbiology
• Genetics

Background:

• Optogenetics enables spatiotemporal control of cellular functions using light.
• Existing optogenetic systems often lack precise color discrimination.
• Controlling gene expression in bacteria with light offers novel research and application possibilities.

Purpose of the Study:

• To engineer *Escherichia coli* with the ability to distinguish and respond to red, green, and blue (RGB) light.
• To develop a genetically encoded system for light-inducible gene expression in bacteria.
• To demonstrate the utility of this system in controlling cellular behavior.

Main Methods:

• Designed and implemented a novel genetic circuit in *Escherichia coli* for RGB light sensing.
• Utilized distinct photoreceptor and signaling pathways for each light color.
• Integrated the system with downstream gene expression modules, including pigment production and CRISPR interference (CRISPRi).

Main Results:

• Successfully engineered *E. coli* to exhibit distinct gene expression patterns in response to red, green, and blue light.
• Demonstrated the creation of 'color photographs' on bacterial plates by spatially controlling pigment production.
• Showcased the ability to redirect metabolic flux through light-controlled expression of CRISPRi guide RNAs.

Conclusions:

• The developed RGB optogenetic system provides unprecedented color-specific control over gene expression in *E. coli*.
• This technology enables novel applications in synthetic biology, such as microbial imaging and metabolic engineering.
• The system offers a powerful platform for precise spatiotemporal manipulation of bacterial functions.