Mycorrhiza refers to the symbiotic association between plant roots and specialized soil fungi. This relationship is one of the most important biological processes in terrestrial ecosystems and modern agriculture, yet it remains largely invisible belowground. Through mycorrhizal networks, plants gain access to water and nutrients beyond the reach of their roots, while fungi receive carbon compounds produced by photosynthesis.
In agricultural systems, understanding and supporting mycorrhiza is increasingly important as farmers face declining soil health, nutrient inefficiencies, and climate-driven stress. Mycorrhizal fungi enhance nutrient uptake, improve drought tolerance, and contribute to long-term soil structure, making them a cornerstone of sustainable crop production.
Mycorrhiza is derived from the Greek words mykes (fungus) and rhiza (root). It describes a mutually beneficial relationship in which fungi colonize plant roots and extend their hyphae into the surrounding soil.
A mycorrhiza (plural: mycorrhizae or mycorrhizas) is a symbiotic association—most often mutualistic, though occasionally neutral or weakly pathogenic—between a fungus and the roots of a plant. In this association, the fungus colonizes the host plant’s root system and becomes an integral component of the soil–plant interface.
Mycorrhizal fungi colonize plant roots in two principal ways:
Intracellular colonization, as seen in arbuscular mycorrhizal fungi (AMF), where fungal structures form inside root cortical cells.
Extracellular colonization, as in ectomycorrhizal fungi, where fungal hyphae form a sheath around the roots and penetrate between cells rather than entering them.
Mycorrhizae are a fundamental component of soil life and soil chemistry, influencing nutrient cycling, soil aggregation, and plant productivity across nearly all terrestrial ecosystems.
Mycorrhizae form mutualistic relationships with the roots of the vast majority of land plants. Although only a fraction of plant species have been examined in detail, evidence indicates that approximately 95% of plant families are predominantly mycorrhizal.
In this mutualism:
The plant supplies carbon to the fungus in the form of carbohydrates.
The fungus supplies water and mineral nutrients to the plant.
This exchange is not passive. It is regulated by both partners and responds dynamically to nutrient availability, environmental stress, and plant demand.
In a mycorrhizal association, the fungus gains relatively constant and direct access to carbohydrates such as glucose and sucrose produced through photosynthesis. These carbohydrates are transported from their source tissues (primarily leaves) to roots and then transferred to fungal partners.
In return, the plant benefits from the mycelium’s vastly greater absorptive capacity for water and mineral nutrients. This advantage arises from the large surface-area-to-volume ratio of fungal hyphae relative to plant roots.
Plant roots alone may be unable to efficiently acquire certain nutrients—particularly phosphorus, which is often present in forms that are poorly mobile or chemically bound in soil, especially in alkaline or highly weathered soils. Mycorrhizal mycelium can access these phosphorus pools and transfer them to the plant, significantly improving nutrient acquisition.
The mechanisms by which mycorrhizae improve nutrient uptake are both physical and chemical.
Mycorrhizal hyphae are much smaller in diameter than even the finest plant roots. This allows them to:
Explore soil micropores inaccessible to roots
Extend several centimeters to meters beyond the root depletion zone
Increase the effective root-zone surface area many times over
Fungal cell membranes differ fundamentally from plant membranes. Mycorrhizal fungi can excrete organic acids and enzymes that:
Mobilize bound nutrients
Displace ions from soil particles
Increase nutrient solubility in the rhizosphere
These mechanisms make mycorrhizae especially beneficial in nutrient-poor, compacted, or chemically challenging soils.
Plants colonized by mycorrhizal fungi are often more resistant to:
Soil-borne pathogens
Drought stress
Salinity
Heavy metal toxicity
These benefits arise from multiple interacting factors, including improved water and mineral uptake, altered root exudation patterns, physical occupation of infection sites, and enhanced activation of plant defense pathways.
Plants grown in sterile soils or artificial growth media frequently perform poorly unless mycorrhizal fungi are introduced. Without fungal colonization, nutrient acquisition—especially phosphorus and micronutrients—is often severely limited.
In early successional environments and degraded landscapes, the absence of mycorrhizal fungi can significantly slow plant establishment and growth. Mycorrhizae play a key role in soil restoration, facilitating vegetation establishment and initiating nutrient cycling processes.
Mycorrhizae are widely regarded as one of nature’s most effective biological systems for enhancing productivity while maintaining sustainability. Over decades of research, their benefits have been consistently documented across crops and ecosystems.
Expansion of nutrient acquisition zones far beyond the root system
Improved uptake of phosphorus and immobile micronutrients such as zinc, copper, iron, molybdenum, cobalt, and magnesium
Increased photosynthetic rates and biomass production
Enhanced tolerance to drought, salinity, heat, and heavy metal stress
Increased resistance to soil- and root-borne pathogens
Improved soil aggregation and structural stability
Contribution to long-term soil fertility and land restoration
Mycorrhizal fungi are also uniquely resilient. They produce resting structures such as spores that allow them to survive unfavorable environmental conditions and resume activity when conditions improve.
Mycorrhizae exhibit extraordinary ecological adaptability. They occur in environments ranging from deserts and tropical forests to temperate agricultural systems and arctic ecosystems. A single mycorrhizal species can associate with a wide range of plant hosts, contributing to ecosystem stability and productivity across diverse conditions.
Mycorrhizae are the only fungal system widely recognized as a biofertilizer, due to their consistent and direct role in nutrient acquisition. By improving nutrient efficiency, mycorrhizae can reduce dependence on chemical fertilizers—sometimes by substantial margins—while maintaining or improving crop performance.
They also support soil conservation by stabilizing aggregates, reducing erosion, and restoring degraded land productivity.
Mycorrhiza is not a supplemental feature of plant growth—it is a foundational biological system that underpins nutrient acquisition, soil structure, plant resilience, and ecosystem stability. By extending the functional root system and integrating plants into complex soil networks, mycorrhizae enable sustainable productivity in both natural and agricultural systems.
Supporting mycorrhizal function is therefore not optional for long-term soil health and crop resilience—it is essential.
Smith, S. E., & Read, D. J. (2008). Mycorrhizal symbiosis (3rd edition). Academic Press.
https://www.sciencedirect.com/book/9780123705266/mycorrhizal-symbiosis
Brundrett, M. C., & Tedersoo, L. (2018). Evolutionary history of mycorrhizal symbioses and global host plant diversity. New Phytologist, 220(4), 1108–1115.
https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.14976
van der Heijden, M. G. A., Martin, F. M., Selosse, M. A., & Sanders, I. R. (2015). Mycorrhizal ecology and evolution. New Phytologist, 205(4), 1406–1423.
https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.13288
Food and Agriculture Organization of the United Nations (FAO). Soil biodiversity and ecosystem services.
https://www.fao.org/soils-portal/soil-biodiversity/en/
Photo source and credit: Premier Tech. https://www.pthorticulture.com/en-us/training-center/mycorrhizae-and-plants-make-great-allies and Wikipedia Commons.
Mycorrhiza on Wikipedia: https://en.wikipedia.org/wiki/Mycorrhiza