Projects

We study the evolution of pathogenicity of bacteria on plants and the role mobile genetic elements (MGEs) such as plasmids and bacteriophage play in this. We examine the co-evolution of MGEs with bacteria within plant environments . A deeper understanding of pathogen evolution will aid disease diagnostics, prediction of disease emergence and inform the design of management strategies to mitigate crop losses.

Prophage-mediated virulence evolution 

Viruses that infect bacteria (bacteriophage) are the most abundant lifeforms on Earth. Many bacteriophage infect bacteria and undergo lysogeny whereby their genome is integrated into the bacterial genome and the bacteriophage becomes dormant, replicating with the bacteria DNA and only activating and lysing bacteria under stressful conditions. These dormant phages, or prophages, often carry important genes that can alter bacterial phenotypes such as antibiotic resistance and virulence-related genes. The reactivation of prophage and subsequent lysis of the bacterial host means that prophages are major vehicles of horizontal gene transfer in bacteria. The role of phages in killing bacteria and transferring bacterial genes is well known. However, how these processes are regulated in complex environments and the impact on bacterial phenotypes such as virulence are important questions.

  • How do the phage impact the effector evolution and function

  • What conditions impact phage movement in the plant environment

  • What is the host range of these phages and how does gain of these phages alter bacterial pathogenicity

Plasmid compatibility in plant pathogenic bacteria

Many genes involved in virulence phenotypes are encoded on plasmids in plant pathogens. Closely related strains can have almost identical core genomes but vastly different plasmid repertoires. This translates to differences in virulence and host specificity. We use population genomics techniques to track and characterise plasmid diversity and genes involved in host compatibility.

Plasmid gel of closely related Pseudomonas syringae pv. morsprunorum strains

(Hulin et al. 2018)

Plasmid with coronatine toxin biosynthesis cluster

Mobile Genetic Element (MGE) ecology and evolution

We are employing emerging “omics” techniques to examine mobile genetic elements in bacterial communities in the field to understand their diversity, bacterial host range, ecology and evolution.