Controlling the Expression of Heterologous Genes in Bdellovibrio bacteriovorus HD100 using Synthetic Biology strategies
Bdellovibrio bacteriovorus HD100 is an obligate predatory bacterium that preys upon Gram-negative bacteria. It has been proposed to be applied as a “living antibiotic” in several fields such as agriculture or even medicine, since it is able to prey upon microbial pathogens. Its interesting lifestyle makes this bacterium very attractive as a microbial chassis for co-culture systems including two partners. A limitation to this goal is the scarcity of suitable synthetic biology tools for predator domestication. To fill this gap, we have firstly adapted the hierarchical assembly cloning technique Golden Standard (GS) to make it compatible with B. bacteriovorus HD100. The chromosomal integration of the Tn7 transposon's mobile element, in conjunction with the application of the Golden Standard technique, has facilitated the systematic characterization of a repertoire of constitutive and inducible promoters, facilitating the control of the expression of heterologous genes in this bacterium. PJExD/EliR proved to be an exceptional inducible promoter in B. bacteriovorus HD100 when precise regulation is essential while the synthetic promoter PBG37 showed a high expression. These genetic tools represent a step forward in the conversion of B. bacteriovorus into an amenable strain for microbial biotechnology approaches.