Kingdom Fungi – Structure, Classification, Characteristics, FAQs

A scientific method for grouping and subgrouping organisms according to their similarities and differences is called biological classification. The basic goal of biological categorization is to group the enormous variety of living things into groups that can be clearly labeled and recalled in the future. It took years for researchers to establish the most important traits for the classification, and numerous biologists have contributed to this process.

Kingdom Fungi 

• There is a huge diversity of organisms that are neither plants nor animals in the kingdom of Fungi.
• Eating examples of these distinctive multicellular eukaryotes include mushrooms and yeast, which cause our bread to rise and ferment our beer and wine. And every ecosystem entirely depends on their impact on our planet as decomposers.
• To name a few, fungi are also organisms that cause black spots to grow on bread that has been left outside for a few days, mushrooms, and yeast cells, which are frequently used to make beer and bread. Additionally, they are present in the majority of fungal illnesses, including skin infections.
• All of the examples we gave feature damp environments if we look closely. We can therefore conclude that fungi typically grow in environments that are both moist and warm enough to support them.
• The creatures that make up the Kingdom of Fungi are pervasive and have a cell wall. They fall under the category of heterotrophs among living things.

Classification of Kingdom Fungi 

Based on the morphology of the mycelium, and the manner of spore generation, the kingdom of fungus is separated into numerous classes, including. 

Phycomycetes

• Members of the Phycomycetes group can be found as obligatory parasites on plants, on decaying wood in moist environments, and in aquatic settings.
• The mycelium is coenocytic and aseptate.
• If the gametes have similar morphologies, they are known as isogamous, and if they have different ones, they are known as anisogamous. Asexual reproduction occurs through zoospores or aplanospores.
• Rhizopus and Mucor are examples.
• Oomycetes and Zygomycetes are the two divisions of Phycomycota or Phycomycetes.

 Oomycetes

• Coenocytic mycelium is present (multinucleate and aseptate). Cellulose and other glucans are found in the hyphal wall of numerous species. Cellulose can also be found in some chitin or fungi.
• The development of sporangia, or sacs holding spores, is a component of asexual reproduction.
• The sporangia in watery environments create zoospores. Most biflagellate zoospores have heterokont flagellation, where one flagellum is smooth, and the other is of the tinsel variety (having fine surface outgrowths called mastigonemes). Typically, gametes are not flocculated.
• In terrestrial environments, the sporangia frequently behave like spores, which are comparable to conidia.
• The sporangia are hence frequently referred to as conidiosporangia.
• The male sex organs, or antheridium, transmit their product into the female sex organ, or oogonium, through a fertilization tube, in order to reproduce sexually by gametangial contact. Oospore is the end result of sexual reproduction.

 Zygomycetes 

• These are created when two various cells come together. The asexual spores are known as sporangiospores, while the sexual spores are known as zygospores. The septa are not present in the hyphae.
• Gametangial copulation or conjugation is the method of sexual reproduction.
• Zygomycetes are also known as conjugation fungi of it.
• Mycelium does not directly grow from the zygospore.
• Instead, it creates what is known as a germ sporangium, a new sporangium (previously called zygosporangium).
• Meiospores known as germ spores are produced by germ sporangium.
• Mucor is an example.

Deuteromycetes

• A synthetic class of fungus called Deuteromycetes has been developed to encompass all those fungi whose sexual stage is either unknown or nonexistent.
• The majority of deuteromycetes members may actually be ascomycetes, in which sexual reproduction is either absent or has not yet been identified.
• Some Deuteromycetes resemble yeast-like unicellular organisms.
• They are frequently researched alongside the latter.
• Conidia and other forms of spores frequently serve as the means of asexual reproduction.
• Even asexual spores don’t always exist.
• Typically, the mycelium is septate.
• Unknown coenocytic forms exist.
• There are no clamp connections, which are present in basidiomycetes.

Ascomycetes

• This is often referred to as sac-fungi.
• They are typically seen in multicellular form; unicellular form is uncommon.
• The mycelium of ascomycetes is in a branching and distinct shape.
• They might be parasitic, decomposers, or saprophytes.
• They may be saprophytic, parasitic, decomposers, coprophilous, or any of these. Ascospores are the name for sexual spores. Conidiospores are used in asexual reproduction.
• Aspergillus, Claviceps, and Neurospora, for instance, are a few examples.

Basidiomycetes

• Because their fructifications are frequently huge and noticeable, such as mushrooms (gill fungus), toadstools, puffballs, bracket fungi, etc., basidiomycetes are the most developed and frequently observed fungi.
• Having a sexual partner does not require any organs.
• Instead, a fusion between basidiospores and other monokaryotic spores, between a spore spermatium and a hypha, or between two hyphal cells of primary mycelia results in plasmogamy (fusion of protoplasts without fusion of their nuclei).
• There are roughly 25000 species in the class. Among the best wood decomposers are basidiomycetes. Basidiomycetes are able to outcompete most insects in the decay of hardwoods and woody tree parts. Basidiomycetes have the capacity to break down cellulose and lignin.
• The fungi may or may not produce basidiocarps, which are fructifications.
• The basidiocarps range in size from tiny microscopic structures to enormous macroscopic ones.

Fungi are classified based on the mode of nutrition

Saprophytic- Saprophytic means that they live and feed on dead organic matter. Penicillium, Rhizopus, Mucor, and so on. These are primarily of two types:

• Ectophytic Saprophytes: Fungi that grow on the surface of the water.
• Endophytic Saprophytes: Fungi that grow inside organic matter.

Parasitic-They feed on hosts, which are either living or dead organisms. By spreading disease, they cause harm to the hosts. The parasite-host relationship is referred to as parasitism.

• Based on their location, parasites are classified into two types:
• Parasites known as endoparasites reside inside their hosts’ bodies.
• Ectoparasites live on the host’s surface.

Symbiotic-Symbiotic fungi live in an interdependent relationship with other species that benefits both parties.

Lichens and mycorrhiza are two examples. Lichens are the result of a mutualistic relationship between algae and fungi.

In this case, algae and fungi benefit from each other because fungi provide shelter for algae and algae provide carbohydrates for fungi. Mycorrhiza is a symbiotic relationship that exists between fungi and plants.

Kingdom Fungi Characteristics 

• The fungus is a non-vascular, eukaryotic creature.
• In fungi, sexual reproduction takes place as a result of pheromone generation.
• Fungi develop more slowly than bacteria do.
• They lack chloroplasts, which prevents them from doing photosynthesis.
• Fungal reproduction happens by spores.
• The nuclear envelope does not degrade during mitosis.
• Sexual and asexual reproduction are both possible in fungi.
• Fungi don’t have an embryonic stage.

Kingdom Fungi Reproduction

• Fungi can reproduce both sexually and asexually. Anamorph refers to the asexual way of reproduction while Teleomorph refers to the sexual mode of reproduction.
• Conidia, zoospores, or sporangiospores, which are spores, are used in asexual reproduction.
• Budding, fission, and fragmentation are the three processes used in vegetative reproduction.
• Through ascospores, basidiospores, and oospores, sexual reproduction takes place.
• In the kingdom of fungi, the usual form of sexual reproduction is not always present. In some fungi, a diploid cell does not develop from the union of two haploid hyphae.
• In these circumstances, a transitional stage known as dikaryophase manifests. The emergence of diploid cells comes after this phase.p

Structure of kingdom Fungi

• Almost all fungi, with the exception of yeast cells, have filamentous structures.
• The chromatin threads run through the thick, translucent nucleus. A nuclear membrane surrounds the nucleus.
• Cell walls of fungi are made of chitin and sugars.
• Protoplast, which divides into other cell parts such as the cell membrane, cell organelles, cytoplasm, and nuclei, makes up the cell wall.
• They may be multicellular or single-celled in origin.
• The majority of fungi are made up of hyphae, which are thread-like structures. Mycelium is the term for the structure that these hyphae produce.

Frequently Asked Questions

Question 1: Which kingdom has ties to the kingdom of fungi?

Answer:

Kingdom fungus and the animal kingdom are closely related. This has been shown through phylogenetic analyses. According to the evolutionary tree, mammals and fungi split millions of years ago.

Question 2: What is sexual reproduction like in the kingdom of fungi?

Answer:

Meiosis, karyogamy, and plasmogamy are the three steps that make up the sexual reproduction of fungi. Two daughter cells, each of which has a separate set of chromosomes, are formed from the splitting of the diploid chromosomes.

Question 3: Describe the Deuteromycetes of the fungus kingdom. 

Answer:

• Deuteromycetes Because only the asexual or vegetative phases of these fungi are understood, they are frequently referred to as imperfect fungi.
• The Deuteromycetes solely generate conidia, which are asexual spores. The mycelium is branching and septate.
• Some of them are saprophytes or parasites, but the majority break down waste and aid in the cycling of minerals. Examples include Trichoderma, Colletotrichum, and Alternaria.

Question 4: Describe the process of vegetative reproduction in the fungus kingdom. 

Answer:

This happens by fragmentation, fission, and budding.

• Fragmentation: Some Ascomycotina and Basidiomycotina forms can reproduce by breaking apart the mycelium.
• Some unicelled forms can reproduce by budding. On the parent cell, a bud first appears as a papilla before expanding and becoming an entirely distinct entity.
• Fission: A few unicelled organisms, such as slime molds and yeast, reproduce using this mechanism.

Question 5: Describe the nutritional division of the kingdom fungi. 

Answer: 

• Fungi that are parasites feed off of and absorb nutrients from other living things, such as plants or animals. Examples include Puccinia and Taphrina.
• Fungi that are saprophytes eat decomposing organic substances for food. Examples include Rhizopus, Penicillium, and Aspergillus.
• Fungi that coexist in mutually beneficial relationships with other species are known as symbiotic relationships. Two examples are mycorrhiza and lichens.

Question 6: What function do members of the kingdom fungus play in food and medicine?

Answer:

• Food – The cultivated species of mushrooms are edible and are consumed by people.
• Medicines – A variety of fungi are used to make antibiotics and treat illnesses in both people and animals. The common fungus Penicillin is the source of the antibiotic penicillin.

Question 7: Describe the Basidiomycetes. 

Answer: 

Mushrooms are the most prevalent type of basidiomycota, and they mostly exist as parasites. In basidiospores, sexual reproduction takes place. By means of conidia, budding, or fragmentation, asexual reproduction takes place. Consider Agaricus.