Fungal Friends

When ancient plants first evolved to live on land, they found a harsh and unforgiving environment. On land, water and nutrients are much more difficult to acquire. Compared to the watery habitats they came from, plant roots on land are not surrounded by limitless resources. Chance encounters with several species of fungi forged a timeless and important symbiosis. These fungal symbionts greatly improved the water and mineral uptake of their host plants. In return for these increased resources, the fungi are “paid” in sugars produced by the plant. The term mycorrhiza or “root fungus” is used to describe this uniquely beneficial relationship. Depending on the type of fungi and how they infect the plant, mycorrhizal fungi can be broken into two main categories.

fungal root tips
Tree-like structures of mycorrhizal fungus on root tips. Photo Credit: Ellen Larsson, R. Henrik Nilsson, Erik Kristiansson, Martin Ryberg, Karl-Henrik Larsson (2005). WikiCommons

The Inside Job

Endomycorrhizal fungi have unique traits that separate them from other forms of mycorrhizal fungi. First, they can enter plant cells in the cortex (part of the root). Once inside the cells, they set up special structures called arbuscules. These small “trees” within the plant cell allow for water and minerals to be traded for sugars. Another unique feature is the absence of sexual reproduction in endomycorrhizal fungi. Instead of making mushrooms to reproduce, they form asexual spores. These clonal bodies maintain the species. Endomycorrhizal fungi are commonly found on many plants including most annual vegetables and ornamental plants.

An Outside Ally

Mycelium anchoring in a wood structure.
Mycelium anchoring in a wood structure. Photo credit: Andre Picard, PhD

Unlike endomycorrhiza, ectomycorrhiza are not able to enter the plant’s cells. Instead, they form a specialized structure between the cells in the cortex. This structure is called the Hartig net. This is the location for nutrients and water to be traded for sugars. Ectomycorrhizal fungi also cover the exterior of the plant’s roots with a mantle, or fungal covering. This covering suppresses the growth of root hairs, but the fungus makes up for this by extending the “reach” of the plant’s root system with fungal hyphae (root-like structures of the fungus). These types of fungi are primarily found in association with shrubs, woody plants, and trees. Ectomycorrhizal fungi also produce mushrooms to spread their spores.

Ancient Partnership

This age-old partnership has been a boon for both organisms. The plants have gained access to more water and nutrients. Something that would be much harder without the fungi. The fungi, in return, have gained a food source in the form of carbon. This carbon-based “economy” is what drives the whole relationship. Regardless of whether they are endomycorrhiza or ectomycorrhiza, this ancient symbiosis between plant and fungi has been crucial to the success of land plants.

Need more information?

This information was compiled by Mack Lessig, Community Gardens Program Coordinator for Manatee County Department of Parks and Natural Resources, Ag and Extension Services Division in partnership with the University of Florida/IFAS.  941-722-4524 Ext 1821 or MLessig@ufl.edu

We have a plant diagnostic clinic open to the public on Monday, Tuesday, Thursday, and Friday from 9:00 am to 4:00 pm.  Bring us your landscaping and gardening issues.

If you want to grow avocados commercially, reach out to Lisa Hickey. She is the Sustainable Food Systems Extension Agent who works with the commercial fruit and vegetable producers.  Lisa.Hickey@ufl.edu  Same office number.

1


Posted: March 17, 2022


Category: Agriculture, , Home Landscapes, Horticulture, Natural Resources
Tags: Fungal, Fungus, Mushrooms, Mycorrhizae


Subscribe For More Great Content

IFAS Blogs Categories