Optimizing DNA transduction by selection of mutations that evade bacterial defense systems.

We recently developed a platform where phage-transducing particles optimize DNA delivery to a wide range of hosts. Here, we use this platform to optimize DNA transduction into hosts that naturally restrict specific DNA sequences. We first show that a specific plasmid is restricted for transduction into a particular Salmonella strain. Using the platform, we select for a mutated plasmid that overcomes the restriction barrier. Insertion of the non-mutated sequence into a permissive plasmid restricts transduction. We further show that epigenetic modification enables the DNA to evade restriction by the putative defense system. Our results validate this straightforward genetic approach for optimization of DNA transduction into new hosts.