Assessing the Diversity of Arbuscular Mycorrhizal Fungal Spore Associated Fungi and Bacteria Using Metagenomics and Culturing
Olivia Asher, University of Georgia
Arbuscular Mycorrhizal Fungi (AMF) are microscopic fungi known for their symbiotic relationship with plants. AMF cultivate unique internal and external microbiomes which include bacteria and non-AMF fungi. AMF hyphal microbiome contains members with genes for solubilizing phosphorous, fixing nitrogen, phytohormone production, and more, indicating that these bacteria influence the plant host. To utilize the benefits of AMF in sustainable agriculture, understanding the diversity, assembly, and function of the AMF microbiome is key. AMF spores were obtained directly from agricultural field soil in Arizona and Georgia, and derived pot cultures. Fungal and bacterial amplicon sequences were obtained from popped and un-popped AMF spores to assess the diversity and variability of internal and external microbial associates at a single spore level. Further culturing was performed to isolate spore-associated bacteria and non-AM fungi for whole genome sequencing and further experimentation. Additionally, scanning electron microscopy was used to visualize the spore surface and bacterial partners inhabiting it. Culturing results indicate that bacteria from the genera Arthrobacter, Pseudomonas, and Rhodococcus and non-AMF fungi are found on the surface of AMF spores. Preliminary microscopy results show the presence of bacteria adhering to the surface of AMF spores. Here we present one of the first robust studies of both endophytic bacteria and fungi inhabiting the spores of AMF. It is increasingly clear that the mycorrhizal symbiosis encompasses fungal, bacterial and plant interactions. Understanding how AMF interact with other microbial partners will facilitate improved application of the benefits of AMF in agriculture. The results of this study will provide identification of putative important internal and external fungal and bacterial partners of sorghum-associated AMF for future functional studies.