The Impact of Horizontal Gene Transfer on Bacterial Warfare

Examining how bacteria interact with other bacteria is crucial if we want to understand and manipulate important microbial ecosystems such as the human gut microbiome. We know that these microbial communities are often rife with conflict, as many bacteria engage in inter-bacterial warfare and kill competing bacteria with sophisticated molecular weaponry.

But some of these weapons entail a potential downside. They are encoded on genes that can move between cells, and the bacteria carrying them thus run the risk of providing nearby competitors with their own weapon. While it is known that molecular weapons can be key determinants for who survives in bacterial communities, the effects of weapon genes being passed between bacteria are largely unexplored.

I will fill this gap by making use of one of the major model organisms for understanding bacterial biology - the human gut microbe Escherichia coli.

E. coli bacteria are ideally suited for studying weapon gene mobility as they have many well-described molecular weapons whose genes can be transferred, and they are easy to genetically manipulate. Using these weapon-carrying E. coli bacteria, I will tackle three major open questions in the study of bacterial warfare: 1) How does weapon transmission impact bacterial battles? 2) Are mobile weapon genes sometimes self-serving by propagating themselves at the expense of their bacterial hosts? and 3) Do mobile weapon genes determine which bacteria can invade a microbial gut community?

At the University of Oxford, I will combine genetic engineering with cutting-edge microscopy to visualize and study weapon genes moving between bacteria, and establish a major new research program to understand key aspects of this important and fascinating aspect of microbial life.