Mycorrhiza
Symbiotic association between a fungus and a plant root.
A mycorrhiza is a symbiotic connection between a fungus and a plant, where the fungus’s hyphae link up with the plant’s roots at a cellular level. The name comes from Greek words for “fungus” and “root,” and it describes the fungus’s role in the rhizosphere—the root system and its environment. These associations are key to plant nutrition, soil biology, and soil chemistry. Usually, the relationship is mutualistic, but in some species or situations, it can turn parasitic.
In this partnership, the fungus colonizes the plant’s root tissues, either inside the cells (as in arbuscular mycorrhizal fungi) or between them (as in ectomycorrhizal fungi). The plant produces organic molecules through photosynthesis and shares them with the fungus as sugars or lipids. In return, the fungus provides the plant with water and mineral nutrients like phosphorus, nitrogen, or zinc from the soil. Mycorrhizas are typically found in the roots of vascular plants, but similar associations occur in bryophytes, and fossils show that early land plants without roots also formed arbuscular mycorrhizal links. Most plant species form these associations, though families like Brassicaceae and Chenopodiaceae cannot. The most common type is arbuscular mycorrhiza, present in 70% of plant species, including many crops such as cereals and legumes.
The term “mycorrhiza” was first coined in 1885 by German botanist A.B. Frank. Earlier, in 1881, Franciszek Kamieński showed that the plant *Monotropa hypopitys* depended on fungi from nearby trees for nutrition. In 1899, Noël Bernard found that orchids like *Neottia nidus-avis* need a specific fungus to germinate. During the 20th century, researchers expanded knowledge of mycorrhizal diversity and how widespread it is across plant families. Paleobotanists studying Rhynie chert fossils demonstrated that mycorrhiza-like associations existed 407 million years ago in early land plants. In 2008, the genome of the ectomycorrhizal fungus *Laccaria bicolor* was sequenced, revealing genetic foundations of the symbiosis through gene duplications and specialized secreted proteins, opening the molecular era of mycorrhizal research.
Fossil and genetic evidence suggests mycorrhizae emerged 450–500 million years ago, possibly between fungus-like protists and algae. Arbuscular mycorrhizal relationships appeared first, coinciding with plants moving onto land. Genetic
- first_formal_description
- 1885
- coined_by
- A.B. Frank
- earliest_fossil_evidence
- 407 million years ago (Rhynie chert)
- oldest_mycorrhizal_lineage
- Glomeromycota (arbuscular mycorrhizae)
- percentage_of_plant_species_with_arbuscu
- 70%
- first_ectomycorrhizal_fungus_sequenced
- Laccaria bicolor (2008)
Lore & Background
Mycorrhizal fungi were first formally described and named in 1885 by German botanist A.B. Frank, who coined the term 'mycorrhiza.' Earlier observations by others also contributed to understanding these root-fungal associations. In 1881, Franciszek Kamieński had shown that the plant Monotropa hypopitys relied on fungi from neighboring trees for nutrition, highlighting fungal dependency. Noël Bernard established in 1899 that orchids like Neottia nidus-avis require a specific fungus for seed germination. In the 20th century, researchers expanded understanding of mycorrhizal diversity and prevalence across plant families. Paleobotanists working on the Rhynie chert fossils demonstrated that mycorrhizal-like associations existed 407 million years ago in early land plants. Laccaria bicolor became the first ectomycorrhizal fungus to have its genome sequenced in 2008, revealing the genetic basis of symbiosis through gene duplications and specialized secreted proteins.
Reader's Guide
Mycorrhizae are fundamental to terrestrial plant life. Fossil and genetic evidence indicate that mycorrhizae emerged as early as 450-500 million years ago, potentially between fungus-like protists and algae. Arbuscular mycorrhizal relationships appeared earliest, coinciding with the terrestrialization of plants. Genetic evidence indicates that all land plants share a single common ancestor, which appears to have quickly adopted mycorrhizal symbiosis, and research suggests that proto-mycorrhizal fungi were a key factor enabling plant terrestrialization. There is a strong consensus among paleomycologists that mycorrhizal fungi served as a primitive root system for early terrestrial plants. The earliest direct fossil evidence of early mycorrhizal symbiosis is found in the 407 million year old Rhynie chert. Most plant species form mycorrhizal associations, though some families like Brassicaceae and Chenopodiaceae cannot. The most common is the arbuscular type, present in 70% of plant species, including many crop plants such as cereals and legumes. The modern distribution of mycorrhizal fungi appears to reflect an increasing complexity and competition in root morphology associated with the dominance of angiosperms in the Cenozoic Era.
Did You Know?
- The term 'mycorrhiza' was coined in 1885 by German botanist A.B. Frank.
- The earliest direct fossil evidence of mycorrhizal symbiosis is from the 407 million year old Rhynie chert.
- Arbuscular mycorrhizal fungi belong to the phylum Glomeromycota, the oldest mycorrhizal lineage.
- Laccaria bicolor was the first ectomycorrhizal fungus to have its genome sequenced, in 2008.
More in Fungi And Fungus-Like Organisms 1-24
Spotted an error? Know more?
This is a living reference — every entry is fact-audited, and reader corrections feed straight into our audit queue. Suggest an edit · See this site's audit record