Scientific background
Microbiomes offer great benefits to their hosts, including nutrient acquisition, growth promotion, immunity, and defence against disease but they are complex and difficult to study. As a result, insects have emerged as simple, experimentally tractable models with which to study microbiomes.
Our model is the leafcutter ant Acromyrmex echinatior, which has a simple cuticular microbiome dominated by antibiotic-producing bacteria that protect the ants against disease. The question in this project is how do the ants recruit antibiotic-producing (useful) bacteria while keeping out all other (cheater) bacteria?
Hypothesis
We know the ants pass a single strain of antibiotic-producing Pseudonocardia bacteria from generation to generation. Preliminary data suggest these are bacteriocin-type antibiotics. We have shown in vitro that this vertically transmitted strain could result in selective acquisition of antibiotic-producing Streptomyces bacteria, resulting in a defensive microbiome producing multiple types of antibiotics that is robust to the evolution of resistance by pathogens. Antibiotic-producing bacteria are necessarily themselves antibiotic resistant, and are pre-adapted to the Pseudonocardia-toxin-infused ant cuticle, allowing them to consume nutrients provided by the ants to their cuticular microbiome.
Research methodology
The student will test the prediction that only antibiotic-producing bacteria that are resistant to Pseudonocardia antibiotics can colonise the ant cuticle, and this is why the ants are able to selectively recruit a microbiome dominated by Pseudonocardia and Streptomyces bacteria. This will involve:
1. Identifying the antibiotics made by the Pseudonocardia bacteria.
2. Testing them for activity against a range of different bacteria.
3. Determining their mode(s) of action.
4. Identifying the antibiotic resistance genes (ARGs) that make Streptomyces bacteria resistant.
Training
The student will be based at JIC where Hutchings and Wilkinson share laboratory space equipped for molecular microbiology and natural products chemistry. They will receive full training in microbiology, bioinformatics, antibiotic bioassays, purification of natural products and mass spectrometry.
Training will be provided by the supervisors and their groups, including core funded RAs. Support will also be provided by senior support scientists running bioinformatics, chemistry, metabolomics, and proteomics science platforms at JIC.
Person specification
The student should have a first degree and/or Masters in biology or chemistry.
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