endomykorrhiza

Endomykorrhiza, also known as arbuscular mycorrhiza (AM), is a widespread form of mycorrhizal symbiosis between plants and fungi in the phylum Glomeromycota. In this association, fungal hyphae penetrate the root cortical cells and form arbuscules, highly branched intracellular structures that specialize in nutrient exchange, and sometimes vesicles that function as storage structures. The fungal hyphae extend beyond the root, exploring the soil and increasing the plant’s effective root surface area.

The primary benefit to the plant is enhanced uptake of weather-limited nutrients, especially phosphorus, but also micronutrients and water, acquired via the extensive extraradical hyphae. In return, the plant supplies the fungi with carbohydrates produced through photosynthesis. The interaction is typically mutualistic and perseveres as long as carbon supply and soil conditions support the symbiosis.

Endomykorrhizae occur in a vast majority of land plants, including many crops, woody and herbaceous species, and are common in a wide range of soils. The fungi are obligate biotrophs, dependent on living host tissue for part of their life cycle, and colonization levels are influenced by soil fertility, moisture, pH, and plant species. The association can improve plant drought tolerance, soil structure, and resistance to certain pathogens, contributing to ecosystem function and sustainable agriculture.

Lifecycle involves spore germination, root infection, arbuscule formation, and periodic turnover of intracellular structures, with vesicles serving as fungal storage during non-symbiotic phases.