Phages are major actors in the regulation of microbial diversity and virulence, in particular through their capacity to disseminate bacterial genes in the process called generalized transduction.
Two mechanisms of transductions have been described. The first one is associated with Mu-like phages which multiply their genome by replicative transposition at 50 to 100 sites per bacterial genome. At packaging, phage genomes are released by a nuclease together with bacterial DNA at both ends. The precise distribution of the insertion sites, and the fate of the flanking packaged bacterial DNA which can be a few hundred up to more than three thousands nucleotides long, are not known.
The second one is associated with phages capable of packaging only bacterial DNA, apparently at random, in a process which is not deciphered. We have isolated and characterized new P. aeruginosa bacteriophages performing generalized transduction of both kinds, and have used high-throughput sequencing to analyze bacterial DNA carried by these phages.
We will report new information on transposition features of Mu-like phages, and discuss the existence of preferential insertion sites. We will also present results on the frequency and nature of bacterial DNA packaged by different bacteriophages, with or without integration of the phage genome into the bacterial chromosome.