Projects
evolution in rhizobial communities
All species exist within a complex network of biotic interactions. Evolutionary changes within one pairwise species interaction can cascade through interaction networks, altering the evolutionary trajectory of connected species. The partnership between rhizobia (nitrogen fixing bacteria) and legumes is an intimate and globally important relationship. Rhizobia facilitate the flow of nitrogen from the atmosphere to the plant, while plants provide bacteria with nutrients and shelter in the form of root nodules. However, rhizobia also live as free-living bacteria in the soil where they face interactions with a diverse microbial community. Key members of these soil communities are the temperate phages – bacterial viruses which can play numerous roles in bacterial populations as viral predators, as agents of horizontal gene transfer and as weapons of bacterial warfare.
Collaborators: Peter Young (York), Ville Friman (York), Phil Poole (Oxford), Tim Daniell (Sheffield), Euan James (James Hutton Institute), Pete Iannatta (James Hutton Institute)
Job available
Job available
The role of evolution in plamid mediated host-shifts
https://www.jobs.ac.uk/job/CYC560/research-technician-in-experimental-evolution-in-rhizobia-bis
In many rhizobial species the genes that encode the symbiosis trait - and determine which host a bacterium can partner with - are carried on mobile elements like plasmids. Horizontal gene transfer of these elements is believed to be an important part of the evolutionary ecology of these symbionts, perhaps by generating diversity. We will investigate the role that evolutionary refinement has to play in this process. Is it as simple as ‘plug and play’ symbiosis or do novel symbionts undergo an adaptive step in order to form effective symbioses?
Collaborators: Prof Michael J. Hynes, University of Calgary
bacteria plasmid co-evolution
Conjugative plasmids play a major role in bacterial evolution as vectors for horizontal gene transfer. However acquiring a new plasmid can be highly disruptive to the bacterial cell resulting in strong selective pressure to either loose the plasmid or ameliorate its cost. In this work we have demonstrated that compensatory evolution to alleviate the cost of plasmid carriage is a major force underlying bacteria-plasmid relationships, helping to explain their ubiquity in the environment. These changes can have important consequences for the wider community, affecting co-evolutionary interactions with other partners and the rate of gene transfer in other species. Current work is focused on understanding the mechanisms which underlie these compensatory mutations and the impact of these evolutionary processes in more complex communities.
Collaborators: Mike Brockhurst (Sheffield), Steve Paterson (Liverpool), Andrew Spiers (Abertay), Jamie Hall (Liverpool), Calvin Dytham (York)