Kingdom Fungi – Concept, types, characteristics and examples

We explain what the fungi kingdom is, what its characteristics and classification are. Also, how is their nutrition, reproduction and examples.

What is the fungi kingdom?

The fungi kingdom is one of the groups in which biology classifies known life forms. Is composed of more than 144,000 different species of fungi These include yeasts, molds, and mushrooms, sharing fundamental characteristics such as immobility, heterotrophic feeding, and certain cellular structures.

Mushrooms they exist throughout the world and in different habitats, appearing in different forms and presentations: the traditional idea that we have of them is the mushroom, with a cap and an elongated white body, but this is just one of the numerous species known within the fungi kingdom.

Of all the fungi that inhabit our planet, only 5% have been studied and classified, and it is estimated that there are around 1.5 million species still unknown. This is partly because fungi were formerly classified as a type of plant, until in the 19th century they began to be distinguished as a separate biological kingdom.

The science that specializes in the members of the fungi kingdom is called mycology.

Characteristics of the fungi kingdom

The members of the fungi kingdom share the following fundamental characteristics:

• They lack their own mobility. Fungi grow in soil, on surfaces, or on logs or decaying organic matter, depending on your preferences, but just like plants, they stay in the same place all their lives, unable to move at will.
• They have a cell wall. The cells of fungi are eukaryotic, that is, with a defined cell nucleus, and have a rigid cell wall, similar to that of plant cells, but instead of being composed of cellulose, in fungi it is composed of chitin, the same substance that gives insects the hardness of their exoskeletons. In addition, they are elongated cells that can contain several nuclei, have vacuoles but not chloroplasts, since they do not photosynthesize.
• They grow as hyphae. The growth of fungi occurs as hyphae, cylindrical and uniform structures that can range from a few micrometers to several centimeters in length, being able to overlap in a branching or bifurcation process.

Classification of the fungi kingdom

The classification of fungi has been reworked throughout the history of biology, as better recognition techniques are developed and fungi are distinguished from other protist and chromist life forms that resemble them. The current ranking of the kingdom is as follows:

• Basidiomycete fungi (Basidiomycota). Those that develop mushrooms (basidicarps), from which the reproductive spores of the fungus are born.
• Ascomycete fungi (Ascomycota). Those that instead of mushrooms have asci, spore-producing sex cells.
• Glomeromycetes fungi (Glomeromycota). Mycorrhizae, that is, symbiotic unions between a fungus and the roots of a plant, in which the former provides nutrients and water, and the latter carbohydrates and vitamins that it cannot synthesize.
• Zygomycete fungi (Zygomycota). Zygospore-forming molds, that is, spores capable of withstanding adverse conditions for a long time until they can finally germinate.
• Chytridiomycetes fungi (Chytridiomycota). Those microscopic and primitive fungi, generally aquatic, that reproduce by flagellate spores (zoospores).

Nutrition of the fungi kingdom

The nutrition of fungi is always heterotrophic, that is, they cannot generate their own food like plantsInstead, they must decompose organic matter from other forms of plant or animal life. Depending on how they do it, we can talk about:

• Saprophytic fungi. They feed on the decomposition of waste organic matter, whether specific or not, that is, from a certain exclusive type of organic matter or from anyone in general.
• Mycorrhizal. They are nourished through a symbiotic relationship with plants, colonizing their roots and exchanging with them different mineral nutrients and water, generated by the fungus, in exchange for carbohydrates and vitamins that the fungus is unable to synthesize on its own. This is known as mycorrhiza.
• Lichenized. They are nourished through symbiotic relationships product of the union of the fungus and an alga or cyanobacteria, establishing a relationship so close that they can be considered the same individual. They are similar to mycorrhiza.
• Parasites They feed directly from the body of other living beings, either established on its surface or colonizing inside their body, causing various damages that can be slight or even lethal.

Reproduction of the fungi kingdom

Mushrooms reproduce sexually and asexually, always through the production of spores. These are equivalent to the seeds of trees: forms resistant to the environment that, when the optimal conditions finally occur, germinate and create a new specimen of the fungus. The growth of the hyphae once the spores have germinated can be very fast, and in some cases can be seen with the naked eye (a tropical fungus grows about 5mm per minute).

The spores are formed as the last part of asexual (mitosis) or sexual (meiosis) reproduction processes, depending on whether the fungus needs to spread rapidly, for which asexual replication is preferable, or if it requires genetic variation, for which it will require the exchange of genetic material with other individuals of the same species.

Importance of the fungi kingdom

Fungi carry out an important ecological role in their various niches of appearance, helping the decomposition and recycling of organic mattersuch as dead animals or plants, defecations, dry and fallen leaves, felled tree trunks, etc., along with bacteria and certain species of insects.

Secondly, many species of fungi are useful to humans, either as edible species, such as the mushroom, or as decorative species in gardening. The importance of yeasts in the processes of making beer, bread and other products should also be highlighted, in which they play a vital role in the biochemical transformation of substances.

Toxic or poisonous mushrooms

There are species of fungi that secrete dangerous toxinsSome can even be lethal if ingested, or if their spores are breathed in for a long time. These toxic enzymes can induce in humans or other animals conditions such as tachycardia, vomiting, colic, cold sweat, thirst, bloody excretions or even the decompensation of blood pressure, depending on the amount consumed. These effects can lead, without treatment, to cause necrotic damage to the liver and kidneys, which can lead to death. In other cases, on the other hand, the toxic effects are mild and can be lysergic, that is, hallucinogenic, so its recreational ingestion can occur in some human communities.

There is no simple rule of thumb to distinguish poisonous from edible mushrooms..

Examples of the fungi kingdom

Some common examples of fungi are:

• The mushroom mushroom (Agaricusbisporus). Farmed on farms and part of the regular diet of many countries.
• Athlete’s foot fungus (Trichophytonrubrum). One of the 42 species of parasitic fungi that can infect human skin, in those cases where it is constantly subjected to humidity.
• The Indian bread mushroomCyttariaharioti). A species that parasitizes the trunks of the trees of the American South (Chile and Argentina), generating tumors or yellowish “knots” that obstruct the sap ducts, as well as edible fruits called “Indian bread”.
• The corn fungus (Ustilagomaydis). Also called huitlacoche or cuitlacoche, it is a fungus that grows between the grains of corn, generating edible structures that in Mexico and other countries are considered a delicacy.