Bacteriophage (phage) are viruses that specifically infect bacterial and archaea. Phage is the most diverse and abundant biological entity on the planet. For more than a century, phage is one of the most important model organisms in the molecular biological research. Many important discoveries upon phage research have enabled us to understand the mechanisms of genetic materials in biological activities, and many phage-derived enzymes are greatly useful in the molecular biological research. Phage has also been recognized as natural antimicrobial agents for treating the bacterial infections. In particular, nowadays, the concern related to the emergence of bacteria resistance to multiple antibiotics is increasing. However, the challenges in phage therapy, such as narrow host range and bacterial resistance, limited the application of phage therapy in treating the diseases of antibiotic-resistant bacterial infections. Novel strategies are needed to be developed to overcome the hurdles associated with phage therapy. Synthetic biology aims to design and reprogram new biological systems according to the known principles. Because of their relatively small genome size (5—735 kb), fast growth rate, ease of genetic manipulation, and simple structure, phages have become the most important biological system for synthetic biology research. In this review, we discuss the advances of synthetic biology facing the major challenges of natural phages in basic and application research. For example, synthetic biology has been applied to enhance the infection efficiency of phages, improve the phage biosafety, alter the phage host ranges, adjust the bacterial communities, and knock out the specific bacterial genes. We also present some examples to show the methods that were widely used for phage engineering to obtain phages with new functions. In addition, phage display and phage-assisted continuous evolution have also become powerful tools in synthetic biology. In short, the development of synthetic biology will inspire scientists to design modular phages as multifunctional biological agents for clearance of multi-drug resistant bacteria, detection of the pathogen, regulation of bacterial diversity, and drug delivery.

Keywords： phage ; synthetic biology ; synthetic genome ; phage display ; diagnostics ; phage therapy