Characterisation of the <i>Enterobacter bugandensis </i>type VI secretion system in microbial antagonism

These included two new T6SS clusters that have not been previously described. We then investigated the role of the T6SS in microbial antagonism and found that our model isolate produces an offensive T6SS, capable of antagonising both bacteria and yeast. To identify which effectors were responsible for these phenotypes, we then combined bioinformatic and proteomic approaches to identify 26 putative effectors across the genome.

We focused on a subset of effectors for functional characterisation in microbial antagonism and identified an evolved VgrG with metallopeptidase domain that displayed a dual role in bacterial and fungal antagonism. A putative- NAD+/NADP+ glycohydrolase, and -pore-forming effector were also described to mediate anti-bacterial activity. Together, this thesis demonstrates that the T6SS is widespread across <i>Enterobacter</i> strains, and can represent a potent, multifaceted weapon for these species.<br><br><i>Thesis is embargoed until 31 July 2028.</i><br>