arbusculares

Arbuscular mycorrhizal fungi (AMF), commonly referred to as arbuscular mycorrhizas, form a widespread symbiosis with the roots of most terrestrial plants. In this association, the fungus colonizes the root cortex and develops highly branched intracellular structures called arbuscules, which reside within plant cells and are surrounded by a plant-derived membrane. The arbuscular interface is the main site of nutrient exchange between the partners.

AMF belong to the phylum Glomeromycota and are obligate biotrophs, meaning they rely on a living plant host to complete their life cycle. They produce extraradical hyphae in the soil that extend the plant’s effective absorptive area, aiding the uptake of water and nutrients, particularly phosphorus, as well as micronutrients such as zinc and copper. In return, the plant supplies carbon compounds to the fungus. This mutualism can enhance plant growth, drought tolerance, disease resistance, and soil structure.

Evolution and distribution: The arbuscular mycorrhizal symbiosis is ancient, with evidence in early land plants dating back around 400 million years. Today, AMF colonize a vast diversity of plant species across ecosystems, from forests to agricultural fields. They are challenging to culture without host plants, which has historically limited functional studies but recent genomic and ecological work has advanced understanding of their biology.

Ecological and agricultural relevance: AMF influence nutrient cycling, plant community dynamics, and soil carbon storage. In agricultural contexts, inoculation or management practices that support AMF can improve crop performance in low-input systems, though benefits are context-dependent and can be reduced by excessive phosphorus fertilization or incompatible plant–fungus pairings.