Invasive garlic mustard demonstrates stronger relationships with pathotrophic than mycorrhizal fungi

24 Garlic mustard (Alliaria petiolata) has long been known to degrade mycorrhizal 25 mutualisms in soils it invades and may also promote the abundance of microbial pathogens 26 harmful to native plants or alter saprotrophic communities to disrupt nutrient cycling. Phenology 27 of other invasive species, like Lepidium latifolium and Lonicera maackii, plays a role in their 28 interactions with soil microbial communities, and so we may expect garlic mustard phenology to 29 influence its effects on native soil microbiomes as well. Here, we investigate differences in 30 fungal, bacterial, and archaeal community structure, as well as the abundance of key functional 31 groups, between garlic mustard present, absent, and removed treatments in central-Illinois forest 32 soils across different stages of the garlic mustard life cycle. Across its phenology, garlic mustard 33 present soils had different overall fungal community structure and greater abundance of 34 pathotrophic fungi than soils where garlic mustard was absent or removed. However, abundance 35 of ectomycorrhizal and saprotrophic fungi as well as bacterial and archaeal community structure 36 were similar between treatments and did not interact with garlic mustard phenology. The most 37 abundant overall fungal taxon was a plant pathogen, Entorrhiza aschersoniana, that was greatest 38 in garlic mustard present soils, particularly while the plants were flowering. These results 39 support the hypothesis that invasive plants form active relationships with microbial pathogens 40 that could contribute to their overall success in invading ecosystems. 41 42