Bryophyte-microbe interactions on the remote oceanic island of St. Helena

A russet red bryophyte growing on a tree branch in a forest

Epiphytic moss in the cloud forest of St. Helena, image by Silvia Pressel

The aims of this project are to characterise the microbiome community composition of bryophytes and microbe-plant interactions on St Helena Island. 


Bryophytes (mosses, liverworts and hornworts) are major contributors to the functioning and biodiversity of many terrestrial ecosystems. Together with their associated microbial communities, bryophytes play key roles in nutrient cycling; however, many aspects of these communities are poorly understood or completely ignored.  The composition of bryophyte microbiomes is thought to vary across species but is also influenced by habitat and may vary across disturbance gradients. 

Bryophyte microbiomes may comprise a wide range of organisms including nitrogen-fixing cyanobacteria, methanotrophic bacteria and fungi, with associations occurring both below and above ground and ranging from intimate endosymbioses through to more loose epiphytic associations. Interactions between plants and microbes can have a significant effect on the host phenotype, mediating processes such as pathogen resistance, stress tolerance, nutrient acquisition, growth and reproduction. 

To date, most research on plant-microbe interactions has focused almost exclusively on ‘higher’ vascular plants and comparatively little is known about the microbiomes of bryophytes and how bryophytes are influenced by their associated microbial communities and vice versa. 

St Helena is a tiny (121.7 km²) and isolated volcanic island in the South Atlantic Ocean with a mild tropical climate tempered by the ocean that is part of the UK Overseas Territory of St. Helena, Ascension and Tristan da Cunha. It has a unique flora and fauna with an exceptionally high level of endemism. However, biodiversity is severely threatened by anthropogenic pressures such as habitat destruction and invasive species.  Mosses, liverworts and hornworts are an important component of the flora, with most of their diversity found in the remnant fragments of St. Helena native and highly threatened cloud forest in the Peaks National Park.

The aims of the PhD project are to characterise for the first time the microbiome community composition of bryophytes on St. Helena, test for interactions between microbes and fungi, and determine how microbiomes and interactions vary across species, host genotype, habitat type and along disturbance gradients.

This project will take an integrative approach, combining field work on St. Helena with laboratory-based methodologies including state-of-the-art sequencing and imaging techniques and in vitro studies. The PhD student will use DNA sequencing, bioinformatics, statistical and microbial community structure analysis techniques.  The plant-microbe interactions will be studied and documented using in vivo laboratory-based cultivation experiments and scanning electron and light microscopy.

Supervision and training

The PhD student will collaborate with a multi-disciplinary team at the Natural History Museum and Imperial Collage London as well as work directly with the St. Helena's Government, CASE partner on the project.

The PhD student will be part of the NHM postgraduate programme and acquire specialist skills in bryology, molecular biology, DNA sequencing, bioinformatics, field work, laboratory-based cultivation experimentation as well as imagining techniques including scanning electron and light microscopy. They will also have opportunities to receive science communication training.

How to apply

Apply for the project on the NHM careers website by sending your CV, covering letter outlining your interest in the PhD position, relevant skills training, experience and qualifications for the research and a statement of how this PhD project fits your career development plans. Please also include two academic references.

A tree growing in ferns in a misty hillside

Cloud forest in the Peaks National Park, St. Helena, Atlantic Ocean, image by Silvia Pressel 

Apply for this project

Apply for this project through the NHM careers website

Application deadline: Midday (12pm GMT) 7 January, 2022

Read more about the Science and Solutions for a Changing Planet Doctoral Training Partnership (SSCP DTP).

Any questions?

Natural History Museum

Lead supervisor: Dr Silvia Pressel


Imperial College

Prof Martin Bidartondo

Natural History Museum

Dr Anne D. Jungblut

CASE partner: St Helena Research Institute (SHRI), Education & Employment Directorate, St Helena Government.

Dr Rebecca Cairns-Wicks


Field KJ, Bidartondo MI, Rimington WR, Hoysted G, Beerling D, Cameron D, Duckett JG, Leake J, Pressel S  (2019) Functional complementarity of ancient plant-fungal mutualisms: contrasting nitrogen, phosphorus and carbon exchanges between Mucoromycotina and Glomeromycotina fungal symbionts of liverwortsNew Phytologist 223: 908-921 

Klarenberg IJ, Keuschnig C, Colmenares AJR, Jungblut AD, Jónsdóttir IS, Vilhelmsson O. Long-term warming effects on the microbiome and nitrogen fixation associated with the moss Racomitrium lanuginosum in a subarctic alpine heathland: bioRxiv 838581

Rimington WR, Pressel S, Duckett JG, Field KJ, Read DJ, Bidartondo MI (2018) Ancient plants with ancient fungi: liverworts associate with early-diverging arbuscular mycorrhizal fungi. Proceedings of the Royal Society B: Biological Sciences, 285 (1888): 20181600 - 20181600. 

Science and Solutions for a Changing Planet (SSCP) doctoral training partnership

This is a joint project between The Science and Solutions for a Changing Planet (SSCP) Doctoral Training Partnership at Imperial College London and The Natural History Museum.

Funded by