Kingdom Fungi

What is Fungi?

Fungi is a eukaryotic organism that includes microorganisms such as yeasts, moulds, and mushrooms. These organisms are classified under kingdom fungi.

The organisms found in Kingdom fungi contain a cell wall and are omnipresent. They are classified as heterotrophs among the living organisms.

Kingdom Fungi

To name a few – the appearance of black spots on bread left outside for some days, the mushrooms, the yeast cells, commonly used for the production of beer and bread are also fungi. They are also found in most of the skin infections and other fungal diseases.

If we observe carefully, all the examples that we cited involve moist conditions. Thus, we can say that fungi usually grow in places which are moist and warm enough to support them.

Let us have a detailed overview of the structure, classification and characteristics of fungi.

Structure of Fungi

Structure of Fungi

The structure of fungi can be explained in the following points:

1. Almost all the fungi have a filamentous structure except yeast the cells.
2. They can be either single-celled or multicellular organism.
3. Fungi consist of long thread-like structures known as hyphae. These hyphae together form a mesh-like structure called mycelium.
4. Fungi possess a cell wall which is made up of chitin and polysaccharides.
5. The cell wall comprises of protoplast which is differentiated into other cell parts such as cell membrane, cytoplasm, cell organelles and nuclei.
6. The nucleus is dense, clear, with chromatin threads. The nucleus is surrounded by a nuclear membrane.

Characteristics of Fungi

Following are the important characteristics of fungi:

1. Fungi are eukaryotic, non-vascular, non-motile and heterotrophic organisms.
2. They may be unicellular or filamentous.
3. They reproduce by means of spores.
4. Fungi exhibit the phenomenon of alternation of generation.
5. Fungi lack chlorophyll and hence cannot perform photosynthesis.
6. Fungi store their food in the form of starch.
7. Biosynthesis of chitin occurs in fungi.
8. The nuclei of the fungi are very small.
9. During mitosis, the nuclear envelope is not dissolved.
10. The fungi have no embryonic stage. They develop from the spores.
11. The mode of reproduction is sexual or asexual.
12. Some fungi are parasitic and can infect the host.
13. Fungi produce a chemical called pheromone which leads to sexual reproduction in fungi.
14. For eg., mushrooms, moulds, yeast.

Classification of Fungi

Kingdom Fungi is classified based on different modes. The different classification of fungi are as follows:

Based on Mode of nutrition

On the basis of nutrition, kingdom fungi can be classified into 4  groups.

1. Saprophytic – The fungi obtain their nutrition by feeding on dead organic substances. Examples: Rhizopus, Penicillium, and Aspergillus.
2. Parasitic – The fungi obtain their nutrition by living on other living organisms (plants or animals) and absorb nutrients from their host. Examples: Taphrina, and Puccinia.
3. Symbiotic – These fungi live by having an interdependent relationship association with other species in which both are mutually benefited.Examples: Lichens and mycorrhiza. Lichens are the symbiotic association between algae and fungi. Here both algae and fungi are mutually benefited as fungi provide shelter for algae and in reverse algae synthesis carbohydrates for fungi.

Based on Spore Formation

Kingdom Fungi is classified into the following based on the formation of spores:

1. Zygomycetes – These are formed by the fusion of two different cells. The sexual spores are known as zygospores while the asexual spores are known as sporangiospores. The hyphae are without the septa.
2. Ascomycetes – They are also called as sac fungi. They can be coprophilous, decomposers, parasitic or saprophytic. The sexual spores are called ascospores. Asexual reproduction occurs by conidiospores. Example – Saccharomyces
3. Basidiomycetes – Mushrooms are the most commonly found basidiomycetes and mostly live as parasites. Sexual reproduction occurs by basidiospores. Asexual reproduction occurs by conidia, budding or fragmentation. Example- Agaricus
4. Deuteromycetes – They are otherwise called imperfect fungi as they do not follow the regular reproduction cycle as the other fungi. They do not reproduce sexually. Asexual reproduction occurs by conidia. Example – Trichoderma.

Reproduction in Fungi

Reproduction in Fungi

Reproduction in fungi is both by sexual and asexual means. The sexual mode of reproduction is referred to as teleomorph and the asexual mode of reproduction is referred to as anamorph.

Vegetative reproduction – By budding, fission, and fragmentation

Asexual reproduction – This takes place with the help of spores called conidia or zoospores or sporangiospores

Sexual reproduction – ascospores, basidiospores, and oospores

The conventional mode of sexual reproduction is not always observed in the kingdom Fungi. In some fungi, the fusion of two haploid hyphae does not result in the formation of a diploid cell. In such cases, there appears an intermediate stage called the dikaryophase. This stage is followed by the formation of diploid cells.

Uses of Fungi

Fungi are one of the most important groups of organisms on the planet as it plays a vital role in the biosphere and has great economic importance on account of their both benefits and harmful effects.

Following are some of the important uses of fungi:

1. Recycling – They play a major role in recycling the dead and decayed matter.
2. Food – Mushrooms species are edible which are cultured and are used as food by humans.
3. Medicines – There are many fungi which are used to produce antibiotics, which are used to control diseases in humans and animals. Penicillin antibiotic is derived from a common fungi Penicillium.
4. Biocontrol Agents – Fungi are involved in exploiting insects, other small worms and help in controlling pests. Spores of fungi are used as spray-on crops.
5. Food spoilage – Fungi play a major role in recycling organic material and are also responsible for major spoilage and economic losses of stored food.

Examples of Fungi

Following are the common examples of fungi:

• Yeast
• Mushrooms
• Moulds
• Truffles

Frequently Asked Questions

Which organisms belong to kingdom fungi?

Kingdom fungi include mushrooms, yeast, moulds containing filamentous structures called hyphae.

What are the different types of fungi?

The different types of fungi include- Zygomycota, Chytridiomycota, Basidiomycota, Ascomycota, and Glomeromycota.

Which kingdom is closely related to kingdom fungi?

Kingdom fungi are closely related to the animal kingdom. This has been determined by phylogenetic studies. The phylogenetic tree explains how animals converged form fungi millions of years ago.

What is common between plants and fungi?

Plants and fungi both have a cell wall. Both plants and animals are eukaryotes and cannot move.

Which class of kingdom fungi can move?

Chytridiomycota produces flagellated gametes and is the only exception to the group that can move with the help of flagella. these are ancient fungi and are believed to be a connecting link between fungi and animals.