glomeromycota

Glomeromycota is a phylum of fungi that comprises the arbuscular mycorrhizal fungi (AMF). Members form intimate symbioses with the roots of most land plants, colonizing root cortical cells and producing arbuscules that facilitate nutrient exchange. The group is characterized by coenocytic (aseptate) hyphae and thick-walled, multinucleate spores. Historically, Glomeromycota was treated as part of Zygomycota, but molecular studies have established it as a distinct lineage.

In their plant associations, AMF exchange soil nutrients for carbon compounds from the host. They are especially effective at phosphate uptake and can improve nitrogen nutrition, drought tolerance, and soil aggregation. Through these effects, they influence plant growth, community structure, and ecosystem functioning. They typically form arbuscular mycorrhizae, with arbuscules inside root cells and vesicles in soil or in roots acting as storage organs.

Reproduction is predominantly asexual via large, multinucleate spores; a sexual life cycle has not been observed in most species, though genetic data indicate ancient recombination and potential cryptic sex in some lineages.

Diversity: The phylum includes several orders, such as Glomerales, Diversisporales, Archaeosporales, and Paraglomerales, and contains hundreds of described species. The best-known genus is Rhizophagus, including Rhizophagus irregularis, a widely studied model AMF. Other common genera include Claroideoglomus, Funneliformis, and Paraglomus.

Ecological and applied importance: AMF are foundational to terrestrial ecosystems; they are used as inoculants in sustainable agriculture to promote crop nutrient uptake and resilience, though their obligate biotrophic nature can complicate cultivation outside host plants.