Arbuscular Mycorrhizal Fungi (AMF)

Arbuscular mycorrhizal fungi (AMF) play a crucial role in soil and plant health. These fungi form a symbiotic relationship with most terrestrial plants, penetrating plant roots to create structures known as arbuscules. Here, nutrients like phosphorus and nitrogen are exchanged for carbohydrates from the plant, enhancing growth, nutrient availability, and pathogen resistance.

What Are AMF?

AMF are members of the fungal phylum Glomeromycota, which comprises approximately 300 species. These fungi rely on plant associations for carbon and contribute to ecosystems by improving plant nutrient uptake, resilience, and growth.

Key Stages in AM Symbiosis Formation:

  1. Spore Germination: The fungal spore germinates and forms a network in the soil.
  2. Chemical Communication: Plants release strigolactones to attract the fungus, which responds by releasing “myc factors” that prepare the plant root for colonisation.
  3. Root Penetration: The fungus forms an appressorium to enter the root and begins to spread intercellularly.
  4. Arbuscule Formation: Inside root cells, the fungus develops highly branched arbuscules, where nutrient exchange occurs.
  5. Nutrient Gathering: Extraradical hyphae extend into the soil, gathering water, nitrogen, phosphorus, and other nutrients.

Some notable genera include Rhizophagus intraradices, Funneliformis mosseae, and Gigaspora margarita.

Origins and Distribution

AMF date back over 450 million years, with evidence found in ancient plant fossils. Today, these fungi are present in 85–90% of plant species worldwide, inhabiting diverse ecosystems such as forests, grasslands, and deserts. AMF are particularly dominant in soils with high decomposition rates and good nitrogen availability relative to phosphorus.

Benefits of AMF in the Myco Market Garden

Integrating AMF into our “Myco Market Garden” enhances:

  • Plant Nutrition: AMF improve phosphorus and nitrogen uptake, reducing the need for external fertilisers.
  • Crop Yield: Studies show significant increases in the growth of crops like maize, wheat, and onions.
  • Pathogen Resistance: AMF help plants defend against pathogens such as Fusarium and Phytophthora.
  • Drought and Stress Tolerance: By improving water and nutrient uptake, AMF enhance plant resilience in challenging conditions.

How AMF Work in Our System

  1. Establishing Fungal Networks: AMF form extensive underground networks, connecting multiple plants and creating a “common mycelial network” that distributes nutrients and signals.
  2. Boosting Soil Health: AMF contribute to soil structure and fertility, supporting overall ecosystem resilience.
  3. Synergy with Nitrogen-Fixing Bacteria: In legumes, AMF complement nitrogen-fixing bacteria by supplying essential nutrients, creating a mutually beneficial system.

Unique Traits of AMF

  • Genome Adaptations: AMF possess a unique genetic system, with spores containing thousands of nuclei, allowing them to adapt to varying conditions.
  • Symbiotic Evolution: The mechanisms used by AMF may have influenced the evolution of plant-fungal relationships.
  • Exceptional Diversity: AMF exhibit a wide range of forms and functions, defying traditional species classification.

Why AMF Are Essential for Agroecology

AMF are critical for sustainable agriculture, enhancing productivity while reducing reliance on synthetic inputs. By integrating AMF into agroecological designs, we can:

  • Improve crop health and yield.
  • Enhance soil fertility and resilience.
  • Foster biodiversity and ecosystem balance.

At the “Myco Market Garden,” we prioritise understanding and utilising AMF to create a sustainable, resilient, and productive growing environment. Let’s harness the power of fungi to shape a better future for agriculture and the planet.

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