Rhizophagus irregularis (previously known as Glomus intraradices[3][4]) is an arbuscular mycorrhizal fungus used as a soil inoculant in agriculture and horticulture.

Rhizophagus irregularis is also commonly used in scientific studies of the effects of arbuscular mycorrhizal fungi on plant and soil improvement.

[6] Rhizophagus irregularis (previously known as Glomus intraradices) has been found to colonise new plants by means of spores, hyphae or fragments of roots colonized by the fungus [7] Arbuscular mycorrhiza (AM) fungi were thought to have propagated clonally for over 500 million years because of their lack of visible sexual structures and thus were considered to be an ancient asexual lineage.

In numerous scientific studies R. irregularis has been shown to increase phosphorus uptake in multiple plants as well as improve soil aggregation due to hyphae.

In a 2005 study, R. irregularis was found to be the only arbuscular mycorrhizal fungi that was able to control nutrient uptake amounts by individual hyphae depending on differing phosphorus levels in the surrounding soil.