Bacillus subtilis 168 as a unique platform enabling synthesis and dissemination of genomes

Bacillus subtilis Marburg 168 is a unique platform for genome engineering and genome synthesis. Genome scale DNA sequences can be synthesized by repeated integration of small DNA segments in the B. subtilis genome. The small DNA segments are collectively called dominos, and should cover the target genome. The B. subtilis strains which have been designed for use in the domino method are collectively called BGM: Bacillus subtilis Genome for Manipulation. The BGM system has been used to produce various genomes in the B. subtilis genome. The synthesized genomes have been demonstrated to be stably maintained as part of the B. subtilis genome. Instability of the synthesized genomes have been observed in genomes with Guanine plus Cytosine contents much higher or lower than that of BGM. The largest synthesized genome produced using this approach to date is that from Synecchosystis PCC6803, a photosynthetic microbe with a genome size of about 3.5 Mbp. The domino method depends on transformation, using the natural competence of B. subtilis. An alternative DNA uptake system, conjugational transfer, has been studied for the past 20 years. A self-transmissible plasmid named pLS20 has been used for the transfer and delivery of large amounts of DNA between B. subtilis. The BGM system is a unique platform for handling very large amounts of DNA from synthesis to dissemination to other cells, and has broad applications in research and practice.