Testing the risks of chemicals to the Arbuscular Mycorrhiza Symbiosis

Arbuscular mycorrhiza (AM) is a symbiotic relationship between soil fungi and plant roots, benefiting most land plants, including widely grown crops. AM fungi enhance nutrient uptake, stress resilience, and support critical soil ecosystem services like nutrient cycling. In agroecosystems, AM fungi are inevitably exposed to plant protection products (PPPs) such as herbicides, pesticides, and fungicides, with varying impacts on AM symbiosis.

The European Food Safety Authority now recommends including AM fungi in pesticide risk assessments, creating a need for new approaches to screen chemicals and their effects on AM symbioses.

We have developed an innovative method to non-invasively monitor and visualize AM symbiosis in real-time using betalain pigments as in vivo markers in Nicotiana benthamiana roots. Betalain coloration is specific to colonized root tissues, allowing the tracing of fungal colonization over time. This system, combined with image analysis or colorimetric methods, offers higher throughput measurement compared to traditional root microscopy.

This project aims to test the hypothesis that a betalain root symbiosis reporter system will enable field-relevant predictions of the potential risk of chemicals to AM fungi. To test this, the student will combine quantitative imaging, histology, genetic and molecular approaches to establish a medium-throughput small pot root analysis system to study the impact of PPPs on AM symbiosis, using a broad-spectrum fungicide as a positive control.

The student will investigate the system's capability to detect dose-response effects of PPPs on AM symbiosis and assess whether observations in Nicotiana benthamiana predict outcomes in agronomically relevant species. The project also aims to determine if PPP impact on AM root colonization is local or can systemically spread from shoot to root, and to survey genes underpinning observed effects.

The findings will be shared through preprints, publications, and presentations, enhancing understanding of AM symbioses and promoting sustainable agricultural practices. The studentship offers a comprehensive research training experience, including an internship at Syngenta to understand the role of compound screening in PPP development and the scientific and regulatory challenges involved.

This PhD will be based at the Sainsbury Laboratory Cambridge University (SLCU), registered with the University of Cambridge. Students will have access to training opportunities through their university and key bioscience areas like statistics through CTP-SAI, as well as Graduate Training in Leadership and Management from MDS. They will create a Personal Development Plan (PDP) for career and skill development, and undertake industrial placements for research and professional skill development in collaboration with partners.