Studying Arbuscular Mycorrhizal Fungi, Their Endosymbiotic Bacteria, and Their Spores: Challenges and Solutions

Abstract

Arbuscular mycorrhizal fungi (AMF) have broad applications in agriculture and land restoration due to their significance in forming symbiotic relationships with most terrestrial plants. However, the field of AMF is understudied, often extending results from a handful of AMF species to all AMF. Spores are a highly significant but often overlooked aspect of the AMF life cycle. In this honors thesis, I summarize the current knowledge surrounding the significance of spores in the AMF life cycle. Great strides have been made in understanding AMF spore germination, dormancy, and life strategies, but there are also gaps in the knowledge that, if filled, would further advance the various applications and studies of AMF. In particular, past research done on AMF must be revisited in order to: (1) redefine terms and standardize experiments; (2) reinforce genetic work in AMF; and (3) use knowledge from plant and seed experiments to better inform AMF experiments. I then empirically demonstrate that the endobacterium ‘Candidatus Moeniiplasma glomeromycotorum’ can be lost or gained during serial culturing practices, although the mechanisms by which endobacteria are lost or gained. I also show that routine spore processing methods, such as sonication and chemical washes during surface decontamination, can be detrimental to spore survival in some species, and therefore the interpretation of spore viability studies should be carefully considered.