Mycorrhizae are one of the most abundant types of symbiosis in the biosphere, and of great interest to agriculture because they contribute towards improving water and nutrient uptake by crops. From the Greek mycos (“fungus”) and rhizos (“root”), it’s a mutually beneficial cooperation between a fungus and a plant, offering advantages for both parties.
Up to seven types of mycorrhizal symbiosis have been classified, but for practical purposes, there are two main types: ectomycorrhizae and endomycorrhizae. What are their differences? And above all, what advantages do they offer for use in agriculture?
An invasion of the roots to improve crops
In the case of ectomycorrhizae, fungi form a network of hyphae around the plant roots, creating what’s called a “mycorrhizal mantle” without penetrating into the plant’s cells. Ectomycorrhizal fungi form particularly close associations with trees and shrubs in forest environments.
In contrast, endomycorrhizae are more common than ectomycorrhizae, as they can occur in the vast majority of plants. In this case, the fungal mycelium penetrates into the root cortical cells, which is why contact is so much closer. Afterwards, they form structures called arbuscules, and in some cases, even vesicles.
Arbuscules significantly increase the surface area for nutrient uptake, improving efficiency and food exchange with the plant, while vesicles are mainly used as reserve organs.
In these arbuscular mycorrhiza-forming fungi, the mycelium generally increases the absorption area of the plant root by up to 100 times, giving the plant access to more nutrients. But there are exceptional cases such as the Glomus iranicum var. tenuihypharum fungus, which is able to increase the network by an additional four times, as you’ll see later.
To summarize, the main beneficial effects of endomycorrhizal symbiosis are:
- Leads to better water and nutrient uptake, particularly elements that are not very mobile such as phosphorus, copper and zinc.
- Enables the crop to tolerate stresses such as drought and salinity better.
- Contributes to the formation of the soil structure.
Therefore, it’s a mutualistic symbiosis where both parties benefit from exchanging different substances. The fungus is in charge of providing water and mineral nutrients to the plant, while the plant supplies the fungus with processed organic nutrients, mainly carbohydrates. It’s a relationship that proves vital for many plants in the early stages of growth.
Arbuscular mycorrhizae: greater fertilization and disease control
One of the main advantages is that mycorrhizal plants use soil nutrients more efficiently. This lets farms make the most of fertilizers while mitigating pollution problems caused by excess fertilizer use.
But mycorrhizal plants are also able to make better use of organic fertilizers. This is due to the production of phosphatase by the fungi or the existing association between the hyphae of the arbuscular mycorrhizae and the microorganisms involved in organic matter mineralization.
Direct application: the case of Glomus iranicum var. tenuihypharum
These mycorrhizal associations are not only fascinating from a biological perspective, but they also have practical applications to achieve more sustainable agricultural production. One of the most remarkable examples is the endomycorrhizal fungus Glomus iranicum var. tenuihypharum.
This exclusive mycorrhiza-forming fungus by Symborg has been proven to be highly beneficial for agricultural crops by improving nutrient availability in the soil and increasing the plants’ resistance to abiotic stress. Through its hyphae that penetrate into root cells, Glomus iranicum var. tenuihypharum forms arbuscules that increase the efficiency of the uptake of essential nutrients such as phosphorus and nitrogen. It can produce up to four times more extramatrical mycelium than other mycorrhiza-forming fungi. In other words, Glomus iranicum var. tenuihypharum can provide crops a greater amount of water and nutrients, giving it a competitive advantage over other mycorrhizal fungi.
And it’s a truly remarkable mycorrhiza-forming fungus, as another of its characteristics is that its spores are very small (with a diameter of 5–30 micras) and sporulation occurs on the outside of the root hairs. This means that they don’t get clogged or break due to accumulation as with other mycorrhizal fungi, which eventually oblige the plant to expend energy in forming new root hairs.
Using mycorrhizal fungi such as Glomus iranicum var. tenuihypharum in agriculture contributes to the sustainability of the agricultural system and environmental conservation without neglecting profitability. By improving plant health and soil quality, these mycorrhizal fungi contribute towards increasing crop yields and the production of healthier foods.
Do you want to learn about the biostimulant solutions based on the Glomus iranicum var. tenuihypharum fungus that we’ve got for farmers? Discover them here: