The terrestrial isopod holobiont: Exploring the role of the hepatopancreal microbiome in isopod adaptation to metal contamination - NERC GW4+ DTP project

This project is one of a number that are in competition for funding from the NERC GW4+ DTP. The GW4+ DTP consists of the Great Western Four alliance of the University of Bath, University of Bristol, Cardiff University and the University of Exeter plus six Research Organisation partners. The partnership aims to provide a broad training in earth and environmental sciences, designed to train tomorrow’s leaders in earth and environmental science. For further details about the programme, please see http://nercgw4plus.ac.uk/.

Background

In terms of function and ecology, animals are not a singular entities but holobionts, each a product of host and its supporting microbial community.

Therefore, to understand phenotype we need to consider the interdependencies between host and associated microbiome. Terrestrial isopods exploit hemocyanin as a respiratory pigment, synthesised in the hepatopancreas (HP), an organ containing the highest soft tissue copper (Cu) concentration recorded in any terrestrial animal.

The HP is formed by ‘S’ cells responsible for sequestering copper and binuclear ‘B’-cells that contains significant iron (Fe) and lipid deposits. The HP lumen of terrestrial isopods hosts a resident microbial community, which contributes to cellulose degradation and benefits from the nutrients environment of the HP-lumen.

This project will define the mutualistic interactions between microbes and host, exploring the benefits provided to the host by the microbiomes and determining the contribution of specific microbes to metallobiological cycles occurring within the holobiont’s HP.

Project aims and methods

The project aims to define the mutualistic interdependencies between microbiome resident in the hepatopancreas (HP) in terrestrial isopods, using the ecotoxicological model species Porcellio scaber and Oniscus asellus.

Interactions between host and microbiome metal trafficking systems in the HP will be the focus for investigation. The project will explore the holobiont’s metal handling systems in transition of hemocyanin-requiring isopods from high-copper (marine) to low-copper (terrestrial) ecosystems.

The impact of metal contaminated ecosystems on isopods and their microbiome will be studied, as well as exposure of isopods to metal nanoparticles (NPs), providing the duel challenge of metal ions and NP anti-microbial activity.

The relationship between changes in the isopod (HP) microbiome and associated changes to host phenotype will be systematically explored to define the inter-dependency between host and specific microbes.

Experimental approaches will include:

- stable isotope flux analysis tracing Cu-uptake in isopods, from microbiome to host
- meta-‘omic characterisation of HP-microbiome in populations resident in metal contaminated habitats
- characterisation of changes in isopod microbiome under challenge with nanoparticles.

Genetic manipulation of specific components (eg ‘Hepatoplasmas’) of the holobiont, investigating involvement of specific microbial metal-handling systems on the ability of the host to maintain its supply of metal micronutrients.

Candidate

This project would suit a candidate who is highly motivated, with a biology/microbiologist degree with biomolecular skills who is interested in the molecular processes underlying biological systems. Ideally, the candidate would have interest/experience in bioinformatics, genomics and some aspect of molecular ecology.

CASE award

The Centre for Ecology and Hydrology (CEH) is the CASE partner for this project. The teams at the University and CEH have an established relationship and track record of jointly supervising PhD students. You will benefit from the training strengths and research infrastructure provided by both organisations with specific secondments at CEH being an integral component of the project. This project builds on a funded collaboration between us and CEH, including a Sêr Cymru Fellowship and two Marie Skłodowska-Curie training studentships (’Pandora’).

Training

You will learn experimental approaches in Isopod maintenance, metagenomics, microbiology, microbiome manipulation, in situ microbial imaging, ecotoxicology and metallobiology.

These laboratory skills will be complemented with the bioinformatics and phylogenetic skills required to interpret the metagenomic and microbial genomics this generated. Staff at Cardiff School of Biosciences Genomics and Imaging hubs will provide instruction in next generation sequencing and Imaging approaches respectively. Training in bioinformatics will be provided though hands on courses already in place at the University and available to all researchers as well as through contact with Professor Kille.