● The fungal kingdom constitutes a unique group of heterotrophic organisms. They show a great diversity in morphology and habitat.

● Many processes are observed everyday around us due to the actions of fungi. These include:

● The development of mold on the bread and the rotting of oranges.

● The common edible mushrooms and toadstools are also fungi.

● White spots seen on mustard leaves are due to a parasitic fungus.

● Bread and beer are made by fermentation using some unicellular fungi, e.g., yeast.

● Other fungi cause diseases in plants and animals, e.g., wheat rust-causing Puccinia.

● Some are the source of antibiotics, e.g., Penicillium.

`color{blue} ul(mathtt ("PARASITES"))` : Parasites arc those organisms that depend on other living organisms for food and
shelter.

`color{blue} ul(mathtt ("SAPROPHYTES"))` : They are the decomposers. They are those organisms that feed on the dead and decaying organic matter and absorb nutrients from them.

`color{blue} ul(mathtt ("SYMBIONTS"))` : Symbionts are those organisms of two different species, that are equally benefitted and dependent on each other while living in close association with each other.

`color{blue} ul(mathtt ("MYCORRHIZAE"))` : Mycorrhizae are symbiotic association between particular fungi and roots of higher plants.
● Fungi are cosmopolitan and occur in air, water, soil and on animals and plants.

● They prefer to grow in warm and humid places.

● That is the reason we keep food in the refrigerator to prevent it from spoiling due to bacterial or fungal infections.

● Most fungi are heterotrophic and absorb soluble organic matter from dead substrates and hence are called saprophytes.

● Those that depend on living plants and animals are called parasites.

● They can also live as symbionts in association with algae as lichens and with roots of higher plants as mycorrhiza.

`color{blue} ul(mathtt ("HYPHAE"))` : A hypha (plural hyphae, from Greek huphḗ, “web”) is the long, fine and branching filamentous structure that makes up the body (or mycelium) of a multicellular fungus. In most fungi, hyphae are the main mode of vegetative growth. Hey are also present in an oomycete, or actinobacterium.

`color{blue} ul(mathtt ("MYCELIUM"))` : Mycelium is the vegetative part of a fungus, consisting of network of branching, thread-like hyphae . Generally it lives inside the substrate and is not normally visible.

`color{blue} ul(mathtt ("COENOCYTIC"))` : A coenocyte (from Greek: κοινός (koinós) = "common" + κύτος (kýtos) = "box, i.e. cell") is a multinucleate cell which can result from multiple nuclear divisions without their accompanying cytokinesis. Thus, those hyphae which are present as continuous, aseptate tubes filled with multinucleated cytoplasm are called coenocytic hyphae.


● Yeasts are the only exception which are unicellular, rest all the fungi are filamentous.

● Their bodies consist of long, slender thread-like structures called hyphae. The network of hyphae is known as mycelium.

● Some hyphae are continuous tubes filled with multinucleated cytoplasm – these are called coenocytic hyphae. Others have septae or cross walls in their hyphae.

● The cell walls of fungi are composed of chitin and polysaccharides.

`color{blue} ul(mathtt ("Zoospores"))` : Zoospores arc the motile spores which are thin-walled and flagellated and produced for asexual
reproduction by some aquatic fungi and algae. These are produced in the zoosporangium.

`=>` `color{blue} ul(mathtt ("Aplanospores"))` : Aplanospores are the thin walled, non-motile spores, used for asexual reproduction in many terrestrial fungal species.

`=>` `color{blue} ul(mathtt ("Plasmogamy"))` : Plasmogamy is the process of fusion of the protoplasm of two cells or gametes.

`=>` `color{blue} ul(mathtt ("Karyogamy"))` : It follows plasmogamy. Karyogamy is the process of fusion of two nuclei of two fusing cells or gametes.

`=>` `color{blue} ul(mathtt ("Dikaryon"))` : This stage follows plasmogamy and precedes karyogamy. It ai the stage where a cell contains two genetically different nuclei, brought together by plasmogamy.

`=>` `color{blue} ul(mathtt ("Isogamy"))` : Isogamy is the process in which two physiologically and morphologically similar
gametes fuse with each other.

`=>` `color{blue} ul(mathtt ("Anisogamy"))` : Anisogamy is the process in which two physiologically and/or morphologically dissimilar
gametes fuse with each other.

● Reproduction in fungi can take place by different means. It Includes the vegetative means, asexual reproduction and sexual reproduction.

`star` `color{Violet}"Vegetative Reproduction"`:

Vegetative Reproduction occurs by means of:

● `color{Maroon}"Fragmentation"`: In this, the hyphal forms multiply by fragmentation that occurs either accidentally, or, in other fungi, occurs through the production of oidia or arthrospores. These thin-walled spores arise by cleavage of hyphae through splitting of the septa. E.g. Coccoides sp.

● `color{Maroon}"Fission"`: In this, the cell constricts in the centre and divides into two giving rise to new individuals,as seen in members of monera. E.g. Schizoharomyces

● `color{Maroon}"Budding"`: The buds develop from from the protoplasm of the parent cells and eventually become new individuals. E.g. Sacchaomyces


`star` `color{Violet}"Asexual reproduction"`

● Asexual reproduction through vegetative spores through mycelial fragmentation is commonly seen in many fungal species and adds an advantage as it allows faster dispersal than sexual reproduction.

● Asexual spores after germination result in a new hyphae and thereby a new colony.

They are of the following type:

● `color{Maroon}"Sporangiospores/Aplanospores"`: Such spores are produced in special sacs, known as sporangia. E.g. Rhizopus

● `color{Maroon}"Zoospores"`: Spores are motile are called zoospores and produced in zoosporangium. E.g. Saprolegnia

● `color{Maroon}"Conidia"`: In many fungi, asexual spores are produced from the tips of specialized hyphae. The specialized aerial hyphae are known as conidiophores and. the spores as conidia. E.g. Penicilium

These are diagrammatically described by the following figure.
.

`star` `color{Violet}"Sexual reproduction"` :

● Sexual reproduction is by oospores, ascospores and basidiospores.

●The various spores are produced in distinct structures called fruiting bodies.

The sexual cycle involves the following three steps:

● Fusion of protoplasms between two motile or non-motile gametes called `color{Maroon}"plasmogamy"`.

● Fusion of two nuclei called `color{Maroon}"karyogamy"`.

● Meiosis in zygote resulting in haploid spores.

● When a fungus reproduces sexually, two haploid hyphae of compatible mating types come together and fuse.

● In some fungi the fusion of two haploid cells immediately results in diploid cells (2n).

● However, in other fungi (ascomycetes and basidiomycetes), an intervening dikaryotic stage (n + n i.e. two nuclei per cell) occurs; such a condition is called a dikaryon and the phase is called `color{Maroon}"dikaryophase"` of fungus.

● Later, the parental nuclei fuse and the cells become diploid.

● The fungi form fruiting bodies in which reduction division occurs, leading to formation of haploid spores.


There are mainly 5 modes of sexual reproduction, seen in different classes of the kingdom.

● `color{Maroon}"Planogametic copulation"`: Results in diploid oospores E.g. Lower fungi i.e. Chytrids

● `color{Maroon}"Gametangial contact"` : Results in diploid oospores E.g. saprolignia sp

● `color{Maroon}"Gametangial copulation"`: Results in zygospore E.g. mucor sp

● `color{Maroon}"Spermatization"`: E.g. Puccinia

● `color{Maroon}"Somatogamy"`: E.g. Mushrooms

The kingdom Fungi is divided into various classes based on:

● The morphology of the mycelium
● Mode of spore formation
● Nature of fruiting bodies
● Mode of asexual and sexual reproduction.

●`color{maroon}"Habitat"`: They are found in aquatic habitats and on decaying wood in moist and damp places or as obligate parasites on plants.

●`color{maroon}"Morphology of the mycelium"`: The mycelium is aseptate and coenocytic.

●`color{maroon}"Mode of nutrition"`: Most of them are saprophytic or parasitic.

●`color{maroon}"Mode of Asexual Reproduction"`: Asexual reproduction takes place by zoospores (motile) or by aplanospores (non-motile). These spores are endogeneously produced in sporangium.

●`color{maroon}"Mode of Sexual Reproduction"`: It may be oogamous, isogamous or anisogamous and lead to the formation of zygospore or oospore.

●`color{maroon}"Example"`: Mucor, Rhizopus (the bread mould) and Albugo (the parasitic fungi on mustard).

●`color{maroon}"Members"`: They are commonly known as sac-fungi. They are either unicellular, e.g., yeast (Sacharomyces) or multicellular, e.g., Penicillium.

●`color{maroon}"Habitat"`: Ascomycetes occur in terrestrial, marine, and freshwater habitats and many species play a major ecological role as decomposers.

●`color{maroon}"Morphology of the mycelium"`: Mycelium is branched and septate.

●`color{maroon}"Mode of nutrition"`: They are saprophytic, decomposers, parasitic or coprophilous (growing on dung).

●`color{maroon}"Mode of Asexual Reproduction"`: The asexual spores are conidia produced exogenously on the special mycelium called conidiophores. Conidia on germination produce mycelium.

●`color{maroon}"Mode of Sexual Reproduction"`: Sexual spores are called ascospores. These are produced endogenously in sac like asci (singular ascus) which are arranged in different types of fruiting bodies called ascocarps.

●`color{maroon}"Example"`: Sacharomyces, Penicillium( used as antibiotic), Aspergillus ,Claviceps and Neurospora (used extensively in biochemical and genetic work), Morels and baffles (edible and are considered delicacies).

●`color{maroon}"Members"`: Commonly known forms of basidiomycetes are mushrooms, bracket fungi or puffballs.

●`color{maroon}"Habitat"`: They grow in soil, on logs and tree stumps and in living plant bodies as parasites

●` color{maroon}"Morphology of the mycelium"`: Mycelium is branched and septate.

●`color{maroon}"Mode of nutrition"`: They are saprophytic or parasitic.

●`color{maroon}"Mode of Asexual Reproduction"`: The asexual spores are generally not found, but vegetative reproduction by fragmentation is common.

●`color{maroon}"Mode of Sexual Reproduction"`: The sex organs are absent.
• Sexual reproduction( plasmogamy) occurs by Somatogamy (fusion of two vegetative structures of different strains or genotypes). The
resultant phase is dikaryotic.
• The dikaryon ultimately gives rise to basidium (plural: basidia) that are arranged in fruiting bodies called basidiocarps.
• Each basidium develops four basidiospores exogenously on its upper end. These basidiospores germinate to form mycelium.

●`color{maroon}"Example"`: Agaricus (mushroom), Ustilago (smut) and Puccinia (rust fungus).

●`color{maroon}"Members"`: Commonly known as imperfect fungi because only the asexual or vegetative phases of these fungi are known.

●`color{maroon}"Morphology of the mycelium"`: Mycelium is branched and septate.

●`color{maroon}"Mode of nutrition"`: Some members are saprophytes or parasites while a large number of them are decomposers of litter and help in mineral cycling.

●`color{maroon}"Mode of Asexual Reproduction"`: Reproduction is only by asexual spores known as conidia.

●`color{maroon}"Mode of Sexual Reproduction"`: Sexual reproduction is not known or absent but once the sexual forms were discovered, they were moved to Ascomycetes or Basidiomycetes.

●`color{maroon}"Example"`: Alternaria, Colletotrichum and Trichoderma.