Involved in arbuscular mycorrhizal (AM) symbiosis. Required for fungal infection in roots and arbuscule development during AM symbiosis. Highly epressed in roots. Expressed at very low levels in leaves, stems and panicles. Induced in roots 7 weeks after inoculation with the arbuscular mycorrhiza (AM) fungus Glomus intraradices. No visible phenotype under normal growth conditions, but roots of mutant plants are impaired in the interaction with the arbuscular mycorrhiza (AM) fungus Glomus intraradices. Belongs to the CYCLOPS family.