Spores-on-a-Chip: investigations on arbuscular mycorrhizal fungi using novel microfluidic technology
File(s)
Author(s)
Richter, Felix
Type
Thesis
Abstract
The arbuscular mycorrhizal fungi (AMF) form a symbiosis with most terrestrial plants on earth and provide them with soil nutrients and an increased general resilience against environmental stresses. AMF research, however, due to their soil-borne nature, is commonly hampered by soil’s lack of transparency, rendering experiments “black-box” studies. To overcome these issues, this PhD-project set out to fill existing gaps in AMF research, such as morphogenesis and space navigation at the asymbiotic stage, exploiting novel microfluidic technologies.
The first part of the thesis describes and discusses the development of the AMF-SporeChip, a microfluidic device designed to trap and germinate AMF spores and confront asymbiotic hyphae with physical obstacles. After demonstrating the functionality of the final device design, new insights and observations uncovered are detailed. As such, the highly dynamic space navigation repertoire of AMF is analysed, revealing the never before described phenomenon of reversible cytoplasmic retraction. To round off the examination of the fungi’s growth behaviour, a search was started for the Spitzenkörper in AMF. Therefore, tissue-specific fluorescent dyes were introduced into the devices but no Spitzenkörper could be detected.
The second part of the thesis concerns itself with a new device, coined the AMF-AnastomosisChip. This device was specifically developed to isolate and study hyphal fusions, called anastomoses, in AMF. The final device was successfully tested and characterised based on loading performance as well as the growth behaviour of the fungi including anastomosis types and frequency. Furthermore, the establishment of chemical gradients in the device was first modelled and then demonstrated.
The thesis concludes with a presentation of alternative uses of the AMF-SporeChip, involving oxygen sensing as well as cultivation of Mucoromycotina fine-root endophytes (MFRE). Finally, possible future avenues that could be followed with microfluidics-assisted research on AMF are discussed.
The first part of the thesis describes and discusses the development of the AMF-SporeChip, a microfluidic device designed to trap and germinate AMF spores and confront asymbiotic hyphae with physical obstacles. After demonstrating the functionality of the final device design, new insights and observations uncovered are detailed. As such, the highly dynamic space navigation repertoire of AMF is analysed, revealing the never before described phenomenon of reversible cytoplasmic retraction. To round off the examination of the fungi’s growth behaviour, a search was started for the Spitzenkörper in AMF. Therefore, tissue-specific fluorescent dyes were introduced into the devices but no Spitzenkörper could be detected.
The second part of the thesis concerns itself with a new device, coined the AMF-AnastomosisChip. This device was specifically developed to isolate and study hyphal fusions, called anastomoses, in AMF. The final device was successfully tested and characterised based on loading performance as well as the growth behaviour of the fungi including anastomosis types and frequency. Furthermore, the establishment of chemical gradients in the device was first modelled and then demonstrated.
The thesis concludes with a presentation of alternative uses of the AMF-SporeChip, involving oxygen sensing as well as cultivation of Mucoromycotina fine-root endophytes (MFRE). Finally, possible future avenues that could be followed with microfluidics-assisted research on AMF are discussed.
Date Issued
2024-09-27
Date Awarded
2025-03-01
Copyright Statement
Attribution-NonCommercial 4.0 International Licence (CC BY-NC)
License URL
Advisor
Stanley, Claire
Publisher Department
Department of Bioengineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)