VKM has conducted a brief review of possible consequences of introducing the arbuscular mycorrhizal fungus Glomus iranicum var. tenuihypharum into Norway. Although there have not been any documented cases of damage caused by the introduction of similar mycorrhizal fungi, the potential impact is concerning. Most studies on similar mycorrhizal fungi have been done under greenhouse conditions, and there is limited knowledge about outdoor field conditions. The beneficial effects of G. iranicum var. tenuihypharum on plant growth have primarily been tested in southern Europe, and the tests have shown variable success in improving plant growth. The ability of the fungus to form symbiosis with multiple plant species raises concerns about its potential impact on local microbial communities. VKM stresses the high level of uncertainty and limited knowledge about possible environmental effects associated with introducing G. iranicum var. tenuihypharum into Norway.