The members of this group of fungi form symbiotic associations with plant roots in form of intracellular arbuscular mycorrhiza (AM fungi). They are involved in the uptake of nutrients and water and often have a positive effect on plant health. Several are recognised as beneficial organisms that enhance the defence mechanisms of the plant against plant pathogens, nematodes and plant viruses. For example, Rhizoglomus intraradices is a common AM fungus that has antagonistic properties against a variety of plant diseases.
The following genera and individual species of antagonists are currently entered in the system: