Mutualistic relationship between fungi and other organisms Hidden Partners: Mycorrhizal Fungi and Plants

mutualistic relationship between fungi and other organisms

A common example is the relationship between cattle egrets and grazing cattle. is obligately dependent upon another organism (host) for its food and shelter. is defined as a symbiotic relationship between the roots of plants and fungi. Download Citation on ResearchGate | Mutualistic Relationships Between Algae and In such associations, two (or more) systematically distinct organisms soil , mosses, leaves of vascular plants (especially in the tropics), on other lichens. Mycorrhizae are symbiotic relationships that form between fungi and plants. Fungi are heterotropic organisms, and must absorb their food. Each group of mycorrhizal fungi interacts and colonizes its botanical host in a slightly different way.

Mycorrhizal fungi encompass many major groups of the fungus Kingdom and in the past were divided into two non-evolutionarily related groups: Ectomycorrhizal fungi ensheath the root cells but usually do not penetrate them extracellular. Endomycorrhizal fungi penetrate and enter the cells of a plant root intracellular. Modern research has lead to the recognition of seven types of mycorrhizal fungi, subdividing the old, traditional groups. The new nomenclature is often more precise and specific to the associated plant taxa.

The relatively homogenous ectomycorrhizal group largely remains with only the addition of the subgroup ectendomycorrhizas. The endomycorrhizal group has been dismantled, but specific types are now recognized: Vescicular-Arbuscular Mycorrhizas, the Orchid mycorrihzas, and those which associate with the Ericaceae Blueberry family: Fungi and Insect Symbiosis We have previously described examples of symbiosis between fungi and photosynthetic organisms, i.

Today, we will cover examples of symbiosis involving fungi and animals, specifically insects. We hear much less of fungus-animal symbiosis and usually think of such relationship only as one of host-parasitic relationship. However, the true relationship between fungi and animals are often not known. One of the most important drives that may lead to such a relationship is the inability of animals to digest cellulose.

When you think of herbivores, such as horses, sheep, cows, goats, etc. Instead, they have symbiotic bacteria, in their stomach, that have the enzymes that digest the cellulose in the plant material for them.

Other animals do not carry microorganisms in their gut, but rather consume mycelium in well-decomposed plant material as their source of food.

Thus, symbiotic relationships between animals and various microorganisms are probably commonplace. Some examples of those relationships that require more studies include: These fungi are known to grow on different, anatomical parts of arthropod bodies. Some species are known to have a broad range, but others are specific, occurring on only a single species of arthropod. It was even thought that some were restricted to a particular part of the anatomy of the organism on which it is growing.

However, some recent research on this relationship has shed light on this myth that had persisted for many years. With respect to insects, which are arthropods, it was once believed that every species of insects have fungi, in this group, associated with some part of their anatomy. However, more recent studies indicate that there appears to be certain groups of insects that are more prone to infections than others and that even in those groups not all species necessarily have this fungus.

Also, the relationship between the insect and fungus was unknown until recently. It is now believed that the fungi in this group are mild parasites on the insects, i.

Some picture of Laboulbendiomycetes can be found for the following species: Peyritschiella protea on the back of a living Rove Beetle, low magnification imageand ascocarp under the microscope ; Laboulbenia cristata on the legs of a beetle, low magnification image showing ascocarps located only on the upper leg portions of the beetle, and an ascocarp as viewed under the microscope ; Rickia dendroiuli, the ascocarps are located only on the forelegs of the millipede low magnification imageand ascocarp as viewed under the microscope.

As can be seen from comparison of the low magnification and microscope images, the ascocarps are very small, even relative to the insect. Because there have been few studies in this group and much is still not known with respect to the relationship between the fungus and insect. For example, it was once believed that the variations as to where the ascocarps occurred, for a particular species was so specific that it could be found only in a particular body part of the male and a different part of the female of the host species.

This phenomenon was first observed by Peyritsch It was later observed that the variations as to where the ascocarps are borne in the male and female seemed to be based on the mating habit of the insects, i.

However, there are also species in which both sexes of host are equally heavily infested, and in the same position on the integument.

mutualistic relationship between fungi and other organisms

A summary of the Laboulbeniomycetes may be found at the following link. Septobasidium The genus is mostly composed of fungi that form symbiotic relationships with various scale insects.

Fungi and Insects: A Love Story

The genus is a member of the Basidiomycota and forms irregular, flattened, colonies that adhere closely to the bark of leaves of living trees, much like the growth of lichens. The colony may be flattened and only a few millimeters in diameter or may grow around the circumference of a branch. Based on this picture, Septobasidium appears to be nothing more than just another wood inhabiting fungus. However, there is a great deal more to this fungus.

The scale insects can be found in the middle layer of the fungus, in chambers that are only slightly larger than the insects, which are connected with numerous tunnels. Some of these insects are parasitized by the fungus, which have inserted haustoria, specialized feeding hyphae, into the insect body.

Teaching the Fungal Tree of Life-Home

These parasitized individuals are immobile and usually occupy a chamber where they are attached to the plant by their sucking apparatus the suctorial tube. A diagrammatic representation of what has just been described can be found here.

The insect nourishes itself with the plant sap that it obtains through its sucking apparatus, and because the fungus is attached to the insect by haustoria, it is indirectly being nourished by the plant, with the insect serving as a "pumping" conduit. However, why is this not a host parasitic-relationship, favoring the fungus?


There are great benefits to the insects as well. A number of scale insects live within the so-call colony of the fungus and are sheltered from the environment and have their food supply beneath them. In addition, they are also protected from predators. Thus, the fungus colony offers the insects shelter, resulting in them living longer than their free-living counter parts. The fungus colony with the insects may also over-winter without any harm coming to either the fungus or insects.

The following spring, the fungus will continue growth and the female insects will be ready to lay its eggs. The larval stage that emerges will crawl about the colony, and if it should go to the surface, it will pick up the fungal spores, which will adhere to their bodies. It may go back inside its colony of origin. It may crawl to a neighboring colony and join that colony. It may go to an area where there is not a preexisting colony and when the spores that are attached to its body germinates, a new colony of Septobasidium will form.

Although a number of species of Septobasidium are known, they are a poorly studied group and the relationship of the fungus and insect has not been that well studied. Although haustoria are formed in the insect, by the fungus, its affect on the insect has not been well studied. Fungi Symbionts With Colonial Insects The most interesting of the fungus-insect symbiotic relationships are those involving colonial insects.

One of the most important driving forces that result in symbiotic relationships between microorganisms is the inability of animals to digest cellulose. Instead, they have symbiotic bacteria, in their stomach, that have the cellulolytic enzymes that digest the plant material for them. Other animals, such as detritivores, do not carry microorganisms in their gut, but rather consume mycelium in well decomposed plant material as their food source.

Thus, symbiotic relationships between animals and various microorganisms are common. We will look at some examples of animal-fungi symbiosis, or more specifically, insect-fungi symbiosis, which I think are far more interesting than the above examples. Ants, Termites and Mushrooms Social insects have always been of interest because of their seemingly, well ordered societies.

In some of these social insects, the mound-building termites of Africa and Asia, and the leaf-cutting ants of Central and South America, there has evolved a rather unique strategy in the utilization of cellulose-rich plant material. These insects cultivate cellulolytic fungi, in underground gardens, and I'm using the world cultivate in the true sense of the word, because these insects are deliberately growing these fungi.

They establish pure cultures of their fungus. That is they grow only one fungus in their garden, which is not easily done, since there are so many sources of contamination that can occur and prevent their gardens from being successful.

mutualistic relationship between fungi and other organisms

However, these insects are able to keep their gardens pure by constantly weeding out foreign fungi. They also care for their garden by providing suitable a food source, i. So the fungi obviously benefit from this arrangement, but the ants and termites also benefit from this relationship.

mutualistic relationship between fungi and other organisms

Here the fungal hyphae penetrate into the cells of the root cortex, where they produce characteristic branched structures called arbuscules. Reproduction is by asexual spores that are produced underground—there are no aboveground structures or multicellular fruiting bodies, which makes Glomales very difficult to study.

Attine ants and cultivated fungi. These insects cut pieces of plant tissue which they carry to underground nests and feed to cultivated basidiomycetes. The ants then feed on the fungi. When winged female ants disperse to found new nests they carry the fungal inoculum with them.

Termites and Termitomyces basidiomycete In Africa, termites in the subfamily Macrotermitinae cultivate basidiomycetes, much like attine ants. The termites consume plant material and deposit it as fecal material in the nest. Fungi in the next digest the plant tissue and the termites consume the fungi.

mutualistic relationship between fungi and other organisms

As in attine ants, females that disperse to found new colonies bring fungal inoculum with them. Bark beetles and woodwasps and their cultivated fungi These distantly related insects share the habit of colonizing dead trees. In both cases, the fungi inoculate the chambers where the eggs are laid with wood-decaying fungi, including ascomycetes and basidiomycetes. Larvae feed on fungal hyphae. Gut symbionts Neocallimastix spp. Commensalism These are symbioses in which there is no obvious effect on the host.

Some biologists reject the concept of commensalism, insisting that every interaction must have an effect on fitness, positive or negative, no matter how slight. Laboulbeniales ascomycetes are symbionts that occur on the exoskeleton of insects.

mutualistic relationship between fungi and other organisms

Trichomycetes zygomycetes live in the hindgut of aquatic arthropods.