5 September 2022

Most plants on earth form a symbiotic relationship with arbuscular mycorrhizal fungi. In this symbiosis, plants provide the fungi with carbon, and in exchange the fungi provide plant hosts with nutrients such as phosphorus. However, this relationship is vulnerable to exploitation by fungal ‘cheaters’ who may obtain all the benefits of the relationship but do not pay the full cost of cooperation while increasing their own fitness.

Plants infected with cheating mycorrhizal partners may experience a reduction in growth and could also negatively influence the neighbouring plant community. Therefore, identifying cheating fungi and the potential plant species they persist with is crucial in protecting our ecosystems and facilitating successful restoration efforts.

This summer scholarship will use a combination of microscopy and molecular based techniques to identify and characterize cheating arbuscular mycorrhizal fungi from a range of native and exotic plant species. Doing so will allow us to better understand what plant species and traits could be vulnerable to low quality associations and how to better design plant communities and their underground interactions to maximize plant health.

Project Background

The relationship between plants and arbuscular mycorrhizal fungi is the one of the most widespread, ancient, and significant symbioses on the planet. However, the evolutionary persistence and stability of this symbiosis is puzzling. Typically, plants are infected by multiple fungal species, while fungal individuals can simultaneously interact with multiple plant hosts. This can select for fungal ‘cheaters’ that avoid the costs of contributing to the symbiosis while still receiving a share of the carbon supplied by the plant host to all fungal partners. Cheating fungi can easily persist and spread in scenarios where high fungal diversity allows them to hide, or where plant hosts are less discerning or reliant on mycorrhizal fungi for nutrient uptake.

Plant traits such as provenance and root diameter can influence arbuscular mycorrhizal fungal communities. Fine-rooted plants are known to be less reliant on mycorrhizal fungi for nutrient uptake and can harbour a higher diversity of arbuscular mycorrhizal fungi, suggesting they could be vulnerable to cheating partners. Further, exotic plants often lack co-evolved partners in their invaded range and may associate with generalist cheating fungal species; this could be a mechanism used to negatively influence cooccurring natives. This can have long-term consequences for restoration efforts and the preservation of biodiversity in native landscapes. Therefore, understanding the role of cheating symbionts is critical when defining healthy, and productive ecosystems and in designing resistant and resilient ecosystems.

This project will build on a successful experiment characterizing the functional traits of mycorrhizal fungi associated with a wide range of plant species ranging in root traits and provenance. We will test the hypothesis that fungal communities that have shown less benefit to plants will have a higher number of fungal spores (increased fungal fitness and lower plant growth is characteristic of cheating fungi).

Opportunities for learning

The summer scholar will be based at Manaaki Whenua (Lincoln) and receive training in all aspects of the role. The student will gain skills in, microscopy, DNA extraction, PCR, DNA sequencing sample preparation, bioinformatics, and phylogenetic analysis.

In addition to untangling some of the dynamics of cheating between plant and mycorrhizal fungi, this project could likely create one of the largest libraries of single spore arbuscular mycorrhizal fungal cultures in Aotearoa that vary in both mutualistic quality and functional traits. This project will be the gateway for future manipulative experimentation to study the trade and allocation of resources in the underground market of plant-mycorrhizal interactions.

Connection with other research

This project compliments the themes of Titirangi – Defining healthy, productive ecosystems (Pou 1), and Nuku-a-rangi – designing resistant and resilient productive ecosystems (Pou 3). The quality of mutualistic partners is easy to overlook but crucial to consider when defining health, and when looking to design resilient ecosystems. This work will compliment project 1.1. which aims to identify the multi-scale drivers of Kānuka health across Horomaka. By identifying cheating mycorrhizal partners, we will be able to detect their presence in Kānuka stands and examine how climate change and plant stress can influence the ecology of these associations.

Scholarship Amount

A total of $6000 tax free is available for each scholarship. Fortnightly payments will be made for the duration of the scholarship, with the final payment of $1000 on receipt of the approved student project report.

Application Process

Please download and complete the BA Summer scholar student application form 2022 (Word doc) (Word doc).  Send your completed application form, along with a CV and a Cover Letter detailing why you feel you wouldbe suitable for this position.

Email applications to Elena Johnson [email protected] before the closing date 23 September, 2022. 


Location:  Christchurch
Institution: Manaaki Whenua – Landcare Research
Supervisor(s): Dr. John Ramana
Other staff Prof. Ian Dickie (University of Canterbury), Dr. Kate Orwin (Manaaki Whenua – Landcare Research)
Pou:  Pou 1: Titirangi
Project: Project 1.1: Multi-scale integrators of ecosystem health
Application Form:  Download and complete the BA Summer scholar student application form 2022 (Word doc)
Apply to:  Email applications to Elena Johnson [email protected], include a CV and cover letter
Applications close:  Friday 23rd September 2022