endomycorrhizal

Endomycorrhizal refers to a group of mycorrhizal associations in which fungal hyphae penetrate the cortical cells of plant roots, forming intracellular structures known as arbuscules. The most common endomycorrhizal fungi are arbuscular mycorrhizal (AM) fungi, which belong to the phylum Glomeromycota. AM associations are found in a large majority of land plants, including many crops, and are sometimes referred to as vesicular-arbuscular mycorrhizae (VAM).

In AM associations, hyphae extend into the soil and explore nutrients beyond the root depletion zone. Within root cortical cells, the fungal hyphae form highly branched arbuscules that facilitate bidirectional exchange: phosphorus and other minerals and water move from the fungus to the plant, while carbohydrates and lipids move from the plant to the fungus. Vesicles may serve as storage structures in some AM morphotypes. The relationship is largely obligate for the fungus, which depends on plant-derived carbon, while the plant gains access to nutrients and improved soil exploration.

Ecologically, endomycorrhizal symbioses enhance plant nutrient uptake, drought tolerance, and soil structure through hyphal networks and the production of soil-binding proteins like glomalin. They can influence plant community dynamics and resistance to certain soil-borne pathogens, though benefits vary with plant species, soil conditions, and nutrient status. Management considerations include avoiding excessive phosphorus fertilization and certain fungicides that can disrupt AM fungi. Endomycorrhizal associations are a foundational component of many terrestrial ecosystems and sustainable agricultural systems.