Interactions Between An Arbuscular Mycorrhizal Fungi Community From a Cheatgrass-Invaded Soil and Native Steppe Plant Species.

Cheatgrass (Bromus tectorum) invasion is known to alter arbuscular mycorrhizal fungi communities in invaded soils. However, it is unknown how this alteration affects native steppe vegetation, nor how the altered AMF community itself responds to different hosts. To test the hypothesis that native early- and mid-successional steppe vegetation are highly variable in their interactions with the AMF community associated with cheatgrass, 15 common native plant species, along with cheatgrass and big sagebrush (Artemisia tridentate ssp. wyomingensis) were grown in soil collected from an invaded site in southeastern Wyoming. A mycorrhizal responsiveness study was first conducted to observe the effects of the AMF community on different plant hosts. Second, the soils used in the responsiveness study were used to measure responses of the AMF community to each individual host species using Sudangrass as bioassay host to measure root colonization over 30 days. Results were highly variable, with plant species showing responses ranging from highly positive to non-responsive to highly negative. Responses of the AMF community to host identity were equally variable, with some hosts exhibiting significant increases in AMF infection potential, while others had no effect. However, there was no relationship between plant responsiveness and response of the AMF community to a particular host, as some plants that were negatively responsive promoted the highest densities of AMF, while some highly responsive plant species had no effect on AMF density.