Interconnected plant roots and mycorrhizal fungi

Unlock Your Garden's Potential: How Mycorrhizae Can Revolutionize Plant Growth

Soraya Malik in Climate & Environment August 2025 • 4 min read.

"Discover the ancient symbiotic relationship that's key to sustainable phosphorus acquisition and healthier plants."

Phosphorus (P) is vital for plant growth. It's a core component of nucleic acids and phospholipids. Plants usually absorb it as inorganic phosphate (Pi). However, Pi is often scarce because it's not very soluble or mobile in the soil. This creates a Pi-depletion zone around plant roots, hindering their ability to get enough of this essential nutrient.

To overcome this limitation, plants have evolved several strategies to boost Pi uptake and use efficiency. These include root branching, longer root hairs, and the release of organic acids and enzymes to free up Pi in the soil. These processes are carefully managed by the plant's internal Pi sensing and signaling pathways.

Another common way plants deal with P deficiency is by forming a mutually beneficial relationship with soil fungi, known as arbuscular mycorrhiza. Arbuscular mycorrhizal (AM) fungi are obligate biotrophs. They colonize root cortex and develop an external mycelium. This mycelium spreads beyond the root, reaching areas the roots can't.

The Power of Mycorrhizae: A Natural Solution for Phosphorus Uptake

Interconnected plant roots and mycorrhizal fungi

The extraradical mycelia, which is 10 to 40 times more extensive than roots, acts as an extra surface area. It increases the ability to forage for nutrients. It's an adaptation to increase the supply of mineral nutrients to the plant. While the main benefit of AM symbiosis is better P status, AM fungi often enhance uptake of other nutrients like nitrogen, copper, and zinc.

The AM symbiosis appeared about 450 million years ago, coinciding with early land plants. It's believed primitive roots developed with AM fungi and coevolved with them to form the root system of extant vascular plants. AM symbiosis is an innovation for plant adaptation and the first mechanism plants evolved to cope with low Pi availability. AM fungi played a key role in plants colonizing land. This plant-fungus association is evolutionary successful, with over 80% of terrestrial plant species living in symbiosis with AM fungi.

Enhanced Nutrient Acquisition: AM fungi significantly expand the root's reach, improving access to phosphorus and other vital nutrients.
Improved Stress Tolerance: Plants with mycorrhizal associations often show greater resilience to environmental stresses, such as drought and soil toxicity.
Sustainable Gardening: By promoting natural nutrient cycling, mycorrhizae reduce the need for synthetic fertilizers.
Support Biodiversity: AM fungi play a crucial role in soil ecosystems, fostering a healthy and diverse soil food web.

Symbiotic P uptake involves Pi acquisition from the soil solution by extraradical mycelia and translocation to the root for transfer to plant cells. Plants and fungi take up P as negatively charged Pi ions, which possess thermodynamically problems since the cell membrane has an inside negative electric potential and the concentration inside the cell is about 1000 times higher than in the soil solution. Pi transport across the plasma membrane requires metabolic energy and involves high-affinity Pi transporters.

Embracing Mycorrhizae for a Greener Future

Research over the past few years has enhanced our understanding of the mechanisms of Pi transport in AM. Pi flow in a mycorrhizal root can include Pi uptake through the epidermis and through the symbiotic fungus. In most cases, some Pi is delivered via the mycorrhizal pathway, but in others, the plant receives its entire Pi through the fungus. On the plant side, the Pi transporters mediating Pi flow through the mycorrhizal pathway have been identified and they are useful markers for a functional mycorrhiza. On the fungal side, the transporters involved in Pi acquisition have been also characterized, but further studies are re-quired to understand the specific roles of the full complement of the fungal Pi transporters.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1016/j.plantsci.2018.11.011, Alternate LINK

Title: Review: Arbuscular Mycorrhizas As Key Players In Sustainable Plant Phosphorus Acquisition: An Overview On The Mechanisms Involved

Subject: Plant Science

Journal: Plant Science

Publisher: Elsevier BV

Authors: Nuria Ferrol, Concepción Azcón-Aguilar, Jacob Pérez-Tienda

Published: 2019-03-01

Everything You Need To Know

How do arbuscular mycorrhizae (AM) fungi enhance plant growth, particularly concerning phosphorus uptake?

Arbuscular mycorrhizae (AM) fungi form a mutually beneficial relationship with plants, colonizing root cortex and extending an external mycelium into the surrounding soil. This mycelium acts as an extended root system, increasing the plant's access to nutrients like phosphorus, nitrogen, copper and zinc that would otherwise be out of reach. This is especially helpful because inorganic phosphate (Pi) is often scarce in the soil.

Besides symbiosis with arbuscular mycorrhizae (AM) fungi, what other strategies do plants employ to overcome phosphorus deficiency in soils?

Plants have developed several strategies to cope with phosphorus deficiency. These include root branching, longer root hairs, and the release of organic acids and enzymes. However, the symbiotic relationship with arbuscular mycorrhizae (AM) fungi is another crucial adaptation. This symbiosis allows plants to acquire Pi via extraradical mycelia extending the surface area for nutrient absorbtion 10 to 40 times more.

What are the major benefits of arbuscular mycorrhizae (AM) for plant health and sustainable gardening practices?

Arbuscular mycorrhizae (AM) fungi enhance nutrient acquisition by expanding the reach of the plant's root system. They improve stress tolerance, making plants more resilient to drought and soil toxicity. They also support sustainable gardening by promoting natural nutrient cycling and reducing the need for synthetic fertilizers, and foster biodiversity by contributing to a healthy soil food web. Research continues to explore the Pi transport mechanisms in AM, enhancing our understanding of this symbiosis.

How does the extraradical mycelia of arbuscular mycorrhizae (AM) improve a plant's ability to absorb vital nutrients, especially phosphorus?

The extraradical mycelia of arbuscular mycorrhizae (AM) fungi acts as an extension of the plant's root system, increasing the surface area for nutrient absorption. This is crucial for phosphorus uptake, as the mycelia can access phosphorus beyond the Pi-depletion zone near the roots. The Pi is then translocated to the root for transfer to the plant cells. This enhancement contributes to greater plant vitality.

What is the evolutionary significance of the symbiotic relationship between plants and arbuscular mycorrhizae (AM) fungi, and how did it shape plant development?

The symbiotic relationship between plants and arbuscular mycorrhizae (AM) fungi dates back approximately 450 million years, coinciding with the evolution of early land plants. This ancient association suggests that primitive roots developed alongside AM fungi, co-evolving to form the root systems of modern vascular plants. AM symbiosis facilitated plants colonizing the land because it was the first mechanism that helped plants adapt to low Pi availability.