Development and application of an interbacterial DNA delivery system based on M13 bacteriophage.

With the rapid development in synthetic biology, bacterial therapy has been widely applied in disease diagnosis and treatment. A key step in regulating the execution of specific instructions by engineered bacteria in vivo involves the transfer of information between bacteria. Currently, small molecule compounds and proteins are commonly used as carriers for inter-bacterial information transfer. However, DNA, as an information carrier, boasts higher information capacity and ease of editing. Based on this, we have developed an engineered bacterial DNA delivery system using M13 bacteriophage to study the cooperative response mechanisms between bacteria. Firstly, we leveraged the ability of engineered bacteria to secrete phagemid DNA into the extracellular environment via bacteriophages and to acquire phagemid DNA through infection by extracellular phagemids, thereby developing a dynamic phagemid replenishment system. This system can maintain the stability of phagemid DNA in environments lacking antibiotic selection pressure, constructing a stable DNA delivery platform for phagemid output. Subsequently, using this engineered bacterial DNA delivery system, we modularized gene circuits and placed them in two different engineered bacteria. Through DNA transfer, we achieved a cooperative response to signals between the two bacteria, laying the groundwork for multi-bacterial joint regulation. Our research not only provides an effective tool for information transfer in engineered bacteria but also offers a novel approach for multi-bacterial therapy.