molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom,[4] separately from the other eukaryotic kingdoms, which by one traditional classification include Plantae, Animalia, Protozoa, and Chromista
.
A characteristic that places fungi in a different kingdom from plants, bacteria, and some protists is
monophyletic group), an interpretation that is also strongly supported by molecular phylogenetics. This fungal group is distinct from the structurally similar myxomycetes (slime molds) and oomycetes (water molds). The discipline of biology devoted to the study of fungi is known as mycology (from the Greekμύκηςcode: ell promoted to code: el mykes, mushroom). In the past, mycology was regarded as a branch of botany
, although it is now known fungi are genetically more closely related to animals than to plants.
Abundant worldwide, most fungi are inconspicuous because of the small size of their structures, and their
The fungus kingdom encompasses an enormous diversity of
subphyla
.
Etymology
The English word fungus is directly adopted from the
macroscopic structures and morphology of mushrooms and molds;[9] the root is also used in other languages, such as the German Schwamm ('sponge') and Schimmel ('mold').[10]
The word mycology is derived from the Greek mykes (μύκης 'mushroom') and logos (λόγος 'discourse').[11] It denotes the scientific study of fungi. The Latin adjectival form of "mycology" (mycologicæ) appeared as early as 1796 in a book on the subject by Christiaan Hendrik Persoon.[12] The word appeared in English as early as 1824 in a book by Robert Kaye Greville.[13] In 1836 the English naturalist Miles Joseph Berkeley's publication The English Flora of Sir James Edward Smith, Vol. 5. also refers to mycology as the study of fungi.[9][14]
A group of all the fungi present in a particular region is known as
mosses. The fungi are now considered a separate kingdom, distinct from both plants and animals, from which they appear to have diverged around one billion years ago (around the start of the Neoproterozoic Era).[20][21]
Some morphological, biochemical, and genetic features are shared with other organisms, while others are unique to the fungi, clearly separating them from the other kingdoms:
The cells of most fungi grow as tubular, elongated, and thread-like (filamentous) structures called
vesicles—cellular structures consisting of proteins, lipids, and other organic molecules—called the Spitzenkörper.[30] Both fungi and oomycetes grow as filamentous hyphal cells.[31] In contrast, similar-looking organisms, such as filamentous green algae, grow by repeated cell division within a chain of cells.[23] There are also single-celled fungi (yeasts) that do not form hyphae, and some fungi have both hyphal and yeast forms.[32]
Some species grow as unicellular yeasts that reproduce by
Dimorphic fungi can switch between a yeast phase and a hyphal phase in response to environmental conditions.[32]
The fungal cell wall is made of a
arthropods,[34] fungi are the only organisms that combine these two structural molecules in their cell wall. Unlike those of plants and oomycetes, fungal cell walls do not contain cellulose.[35][36]
chemical tests. The biological species concept discriminates species based on their ability to mate. The application of molecular tools, such as DNA sequencing and phylogenetic analysis, to study diversity has greatly enhanced the resolution and added robustness to estimates of genetic diversity within various taxonomic groups.[51]
phytopathology, the study of plant diseases, is closely related because many plant pathogens are fungi.[52]
The use of fungi by humans dates back to prehistory;
Piptoporus betulinus).[53] Ancient peoples have used fungi as food sources—often unknowingly—for millennia, in the preparation of leavened bread and fermented juices. Some of the oldest written records contain references to the destruction of crops that were probably caused by pathogenic fungi.[54]
History
Mycology became a systematic science after the development of the
coenocytic. Septate hyphae are divided into compartments separated by cross walls (internal cell walls, called septa, that are formed at right angles to the cell wall giving the hypha its shape), with each compartment containing one or more nuclei; coenocytic hyphae are not compartmentalized.[59] Septa have pores that allow cytoplasm, organelles, and sometimes nuclei to pass through; an example is the dolipore septum in fungi of the phylum Basidiomycota.[60] Coenocytic hyphae are in essence multinucleate supercells.[61]
Many species have developed specialized hyphal structures for nutrient uptake from living hosts; examples include
haustoria in plant-parasitic species of most fungal phyla,[62] and arbuscules of several mycorrhizal fungi, which penetrate into the host cells to consume nutrients.[63]
Although fungi are
chytrids have lost their posterior flagella.[64] Fungi are unusual among the eukaryotes in having a cell wall that, in addition to glucans (e.g., β-1,3-glucan) and other typical components, also contains the biopolymer chitin.[36]
Macroscopic structures
Armillaria solidipes
Fungal mycelia can become visible to the naked eye, for example, on various surfaces and
Armillaria solidipes, which extends over an area of more than 900ha (3.5 square miles), with an estimated age of nearly 9,000years.[66]
The
apothecium—a specialized structure important in sexual reproduction in the ascomycetes—is a cup-shaped fruit body that is often macroscopic and holds the hymenium, a layer of tissue containing the spore-bearing cells.[67] The fruit bodies of the basidiomycetes (basidiocarps) and some ascomycetes can sometimes grow very large, and many are well known as mushrooms
. The frames were taken approximately 12 hours apart over a period of six days.
The growth of fungi as hyphae on or in solid substrates or as single cells in aquatic environments is adapted for the efficient extraction of nutrients, because these growth forms have high
Paecilomyces lilacinus uses a similar structure to penetrate the eggs of nematodes.[71]
The mechanical pressure exerted by the appressorium is generated from physiological processes that increase intracellular
multicellular structures consisting of somatic and reproductive cells—a feature independently evolved in animals and plants[79]—has several functions, including the development of fruit bodies for dissemination of sexual spores (see above) and biofilms for substrate colonization and intercellular communication.[80]
The fungi are traditionally considered
CO2 fixation via visible light, but instead uses ionizing radiation as a source of energy.[83]
Reproduction
Polyporus squamosus
Fungal reproduction is complex, reflecting the differences in lifestyles and genetic makeup within this diverse kingdom of organisms.
anamorph (asexual reproduction).[85] Environmental conditions trigger genetically determined developmental states that lead to the creation of specialized structures for sexual or asexual reproduction. These structures aid reproduction by efficiently dispersing spores or spore-containing propagules
.
Asexual reproduction
Deuteromycota comprise all the species that lack an observable sexual cycle.[87] Deuteromycota (alternatively known as Deuteromycetes, conidial fungi, or mitosporic fungi) is not an accepted taxonomic clade and is now taken to mean simply fungi that lack a known sexual stage.[88]
ascospores. After dispersal, the ascospores may germinate and form a new haploid mycelium.[94]
Sexual reproduction in basidiomycetes is similar to that of the ascomycetes. Compatible haploid hyphae fuse to produce a dikaryotic mycelium. However, the dikaryotic phase is more extensive in the basidiomycetes, often also present in the vegetatively growing mycelium. A specialized anatomical structure, called a
basidiospores after karyogamy and meiosis.[96] The most commonly known basidiocarps are mushrooms, but they may also take other forms (see Morphology
section).
In fungi formerly classified as
sporangiospores. These sporangiospores allow the fungus to rapidly disperse and germinate into new genetically identical haploid fungal mycelia.[97]
Spore dispersal
The spores of most of the researched species of fungi are transported by wind.
stinkhorns, a group of fungi with lively colors and putrid odor that attract insects to disperse their spores.[108]
Besides regular sexual reproduction with meiosis, certain fungi, such as those in the genera
parasexual processes, initiated by anastomosis between hyphae and plasmogamy of fungal cells.[113] The frequency and relative importance of parasexual events is unclear and may be lower than other sexual processes. It is known to play a role in intraspecific hybridization[114] and is likely required for hybridization between species, which has been associated with major events in fungal evolution.[115]
The earliest fossils possessing features typical of fungi date to the
saprobism, and the development of mutualistic relationships such as mycorrhiza and lichenization.[122] Studies suggest that the ancestral ecological state of the Ascomycota was saprobism, and that independent lichenization events have occurred multiple times.[123]
In May 2019, scientists reported the discovery of a fossilized fungus, named Ourasphaira giraldae, in the Canadian Arctic, that may have grown on land a billion years ago, well before plants were living on land.[124][125][126]Pyritized fungus-like microfossils preserved in the basal Ediacaran Doushantuo Formation (~635 Ma) have been reported in South China.[127] Earlier, it had been presumed that the fungi colonized the land during the Cambrian (542–488.3Ma), also long before land plants.[128] Fossilized hyphae and spores recovered from the Ordovician of Wisconsin (460Ma) resemble modern-day Glomerales, and existed at a time when the land flora likely consisted of only non-vascular bryophyte-like plants.[129]Prototaxites, which was probably a fungus or lichen, would have been the tallest organism of the late Silurian and early Devonian. Fungal fossils do not become common and uncontroversial until the early Devonian (416–359.2Ma), when they occur abundantly in the Rhynie chert, mostly as Zygomycota and Chytridiomycota.[128][130][131] At about this same time, approximately 400Ma, the Ascomycota and Basidiomycota diverged,[132] and all modern classes of fungi were present by the Late Carboniferous (Pennsylvanian, 318.1–299Ma).[133]
Lichens formed a component of the early terrestrial ecosystems, and the estimated age of the oldest terrestrial lichen fossil is 415Ma;
fossil record for this period.[139] However, the relative proportion of fungal spores relative to spores formed by algal species is difficult to assess,[140] the spike did not appear worldwide,[141][142] and in many places it did not fall on the Permian–Triassic boundary.[143]
Sixty-five million years ago, immediately after the Cretaceous–Paleogene extinction event that famously killed off most dinosaurs, there was a dramatic increase in evidence of fungi; apparently the death of most plant and animal species led to a huge fungal bloom like "a massive compost heap".[144]
Taxonomy
Although commonly included in botany curricula and textbooks, fungi are more closely related to
monophyletic origin of fungi.[51][146] The taxonomy of fungi is in a state of constant flux, especially due to research based on DNA comparisons. These current phylogenetic analyses often overturn classifications based on older and sometimes less discriminative methods based on morphological features and biological species concepts obtained from experimental matings.[147]
There is no unique generally accepted system at the higher taxonomic levels and there are frequent name changes at every level, from species upwards. Efforts among researchers are now underway to establish and encourage usage of a unified and more consistent
International Code of Nomenclature for algae, fungi and plants, fungal species could also have multiple scientific names depending on their life cycle and mode (sexual or asexual) of reproduction.[149] Web sites such as Index Fungorum and MycoBank are officially recognized nomenclatural repositories and list current names of fungal species (with cross-references to older synonyms).[150]
The 2007 classification of Kingdom Fungi is the result of a large-scale collaborative research effort involving dozens of mycologists and other scientists working on fungal taxonomy.
The major phyla (sometimes called divisions) of fungi have been classified mainly on the basis of characteristics of their sexual reproductive structures. As of 2019[update], nine major lineages have been identified: Opisthosporidia, Chytridiomycota, Neocallimastigomycota, Blastocladiomycota, Zoopagomycota, Mucoromycota, Glomeromycota, Ascomycota and Basidiomycota.[154]
Phylogenetic analysis has demonstrated that the Microsporidia, unicellular parasites of animals and protists, are fairly recent and highly derived endobiotic fungi (living within the tissue of another species).[121] Previously considered to be "primitive" protozoa, they are now thought to be either a basal branch of the Fungi, or a sister group–each other's closest evolutionary relative.[155]
The
rRNA sequences in ribosomes, suggest that the Chytrids are a basal group divergent from the other fungal phyla, consisting of four major clades with suggestive evidence for paraphyly or possibly polyphyly.[156]
The Blastocladiomycota were previously considered a taxonomic clade within the Chytridiomycota. Molecular data and ultrastructural characteristics, however, place the Blastocladiomycota as a sister clade to the Zygomycota, Glomeromycota, and Dikarya (Ascomycota and Basidiomycota). The blastocladiomycetes are saprotrophs, feeding on decomposing organic matter, and they are parasites of all eukaryotic groups. Unlike their close relatives, the chytrids, most of which exhibit zygotic meiosis, the blastocladiomycetes undergo sporic meiosis.[121]
The
mitochondria but contain hydrogenosomes of mitochondrial origin. As in the related chrytrids, neocallimastigomycetes form zoospores that are posteriorly uniflagellate or polyflagellate.[51]
(the typical cup-like reproductive structure of Ascomycetes) showing sterile tissues as well as developing and mature asci.
Members of the
Entomophthoromycotina.[51] Some well-known examples of fungi formerly in the Zygomycota include black bread mold (Rhizopus stolonifer), and Pilobolus species, capable of ejecting spores several meters through the air.[160] Medically relevant genera include Mucor, Rhizomucor, and Rhizopus.[161]
The
teleomorphs in the Ascomycota.[162] Because the products of meiosis are retained within the sac-like ascus, ascomycetes have been used for elucidating principles of genetics and heredity (e.g., Neurospora crassa).[163]
taxonomists no longer group them in the kingdom Fungi. Nonetheless, studies of the oomycetes and myxomycetes are still often included in mycology textbooks and primary research literature.[168]
were also included in fungi in some classifications, as the group Schizomycetes.
The Rozellida clade, including the "ex-chytrid" Rozella, is a genetically disparate group known mostly from environmental DNA sequences that is a sister group to fungi.[154] Members of the group that have been isolated lack the chitinous cell wall that is characteristic of fungi. Alternatively, Rozella can be classified as a basal fungal group.[146]
The
nucleariids may be the next sister group to the eumycete clade, and as such could be included in an expanded fungal kingdom.[145]
Although often inconspicuous, fungi occur in every environment on
symbionts, degrading organic matter to inorganic molecules, which can then re-enter anabolic metabolic pathways in plants or other organisms.[172][173]
Symbiosis
Many fungi have important
commensal fungi are of no apparent benefit or detriment to the host.[177][178][179]
With plants
plants and fungi is one of the most well-known plant–fungus associations and is of significant importance for plant growth and persistence in many ecosystems; over 90% of all plant species engage in mycorrhizal relationships with fungi and are dependent upon this relationship for survival.[180]
The mycorrhizal symbiosis is ancient, dating back to at least 400 million years.[158] It often increases the plant's uptake of inorganic compounds, such as nitrate and phosphate from soils having low concentrations of these key plant nutrients.[172][181] The fungal partners may also mediate plant-to-plant transfer of carbohydrates and other nutrients.[182] Such mycorrhizal communities are called "common mycorrhizal networks".[183][184] A special case of mycorrhiza is myco-heterotrophy, whereby the plant parasitizes the fungus, obtaining all of its nutrients from its fungal symbiont.[185] Some fungal species inhabit the tissues inside roots, stems, and leaves, in which case they are called endophytes.[186] Similar to mycorrhiza, endophytic colonization by fungi may benefit both symbionts; for example, endophytes of grasses impart to their host increased resistance to herbivores and other environmental stresses and receive food and shelter from the plant in return.[187]
organic carbon by photosynthesis, slow growth, small size, long life, long-lasting (seasonal) vegetative reproductive structures, mineral nutrition obtained largely from airborne sources, and greater tolerance of desiccation than most other photosynthetic organisms in the same habitat.[194]
, showing hyphae, and chlamydospores, which are 2–4 µm
in diameter.
Many fungi are
nematodes, which they capture using an array of specialized structures such as constricting rings or adhesive nets.[208] Many fungi that are plant pathogens, such as Magnaporthe oryzae, can switch from being biotrophic (parasitic on living plants) to being necrotrophic (feeding on the dead tissues of plants they have killed).[209] This same principle is applied to fungi-feeding parasites, including Asterotremella albida, which feeds on the fruit bodies of other fungi both while they are living and after they are dead.[210]
Some fungi can cause serious diseases in humans, several of which may be fatal if untreated. These include
allergies, and fungi from different taxonomic groups can evoke allergic reactions.[216]
As targets of mycoparasites
Organisms that parasitize fungi are known as
biocontrol agents against plant fungal diseases.[217] Fungi can also act as mycoparasites or antagonists of other fungi, such as Hypomyces chrysospermus, which grows on bolete
Mycotoxins are secondary metabolites (or natural products), and research has established the existence of biochemical pathways solely for the purpose of producing mycotoxins and other natural products in fungi.[38] Mycotoxins may provide fitness benefits in terms of physiological adaptation, competition with other microbes and fungi, and protection from consumption (fungivory).[223][224] Many fungal secondary metabolites (or derivatives) are used medically, as described under Human use below.
Pathogenic mechanisms
oxidative burst where the plant produces reactive oxygen species at the site of the attempted invasion. U. maydis can respond to the oxidative burst with an oxidative stress response, regulated by the gene YAP1. The response protects U. maydis from the host defense, and is necessary for the pathogen's virulence.[225] Furthermore, U. maydis has a well-established recombinational DNA repair system which acts during mitosis and meiosis.[226] The system may assist the pathogen in surviving DNA damage arising from the host plant's oxidative defensive response to infection.[227]
DMC1, which is a conserved homologue of genes recA in bacteria and RAD51 in eukaryotes, that mediates homologous chromosome pairing during meiosis and repair of DNA double-strand breaks. Thus, C.neoformans can undergo a meiosis, monokaryotic fruiting, that promotes recombinational repair in the oxidative, DNA damaging environment of the host macrophage, and the repair capability may contribute to its virulence.[227][229]
Many species produce metabolites that are major sources of pharmacologically active drugs.
Antibiotics
Particularly important are the antibiotics, including the
rhizosphere, and at low concentrations as quorum-sensing molecules for intra- or interspecies signaling.[241]
Other
Other drugs produced by fungi include
β-lactam antibiotics, are routinely used in clinical medicine. The shiitake mushroom is a source of lentinan, a clinical drug approved for use in cancer treatments in several countries, including Japan.[248][249] In Europe and Japan, polysaccharide-K (brand name Krestin), a chemical derived from Trametes versicolor, is an approved adjuvant for cancer therapy.[250]
truffles, black trumpets, and porcini mushrooms (Boletus edulis) (also known as king boletes) demand a high price on the market. They are often used in gourmet dishes.[261]
Certain types of cheeses require inoculation of milk curds with fungal species that impart a unique flavor and texture to the cheese. Examples include the blue color in cheeses such as Stilton or Roquefort, which are made by inoculation with Penicillium roqueforti.[262] Molds used in cheese production are non-toxic and are thus safe for human consumption; however, mycotoxins (e.g., aflatoxins, roquefortine C, patulin, or others) may accumulate because of growth of other fungi during cheese ripening or storage.[263]
worldwide. It sometimes lacks the greenish color seen here.
Many mushroom species are
hallucinogenic properties. Historically, fly agaric was used by different peoples in Europe and Asia and its present usage for religious or shamanic purposes is reported from some ethnic groups such as the Koryak people of northeastern Siberia.[268]
As it is difficult to accurately identify a safe mushroom without proper training and knowledge, it is often advised to assume that a wild mushroom is poisonous and not to consume it.[269][270]
In agriculture, fungi may be useful if they actively compete for nutrients and space with
herbivory, but several endophyte alkaloids can poison grazing animals, such as cattle and sheep.[276] Infecting cultivars of pasture or forage grasses with Epichloë endophytes is one approach being used in grass breeding programs; the fungal strains are selected for producing only alkaloids that increase resistance to herbivores such as insects, while being non-toxic to livestock.[277][278]
^Moore RT (1980). "Taxonomic proposals for the classification of marine yeasts and other yeast-like fungi including the smuts". Botanica Marina. 23: 361–373.
^Persoon, Christiaan Hendrik (1796). Observationes Mycologicae (in Latin). Vol. Part 1. Leipzig, (Germany): Peter Philipp Wolf. Archived from the original on 19 December 2013. Retrieved 30 March 2019.
^Smith, James Edward (1836). Hooker, William Jackson; Berkeley, Miles Joseph (eds.). The English Flora of Sir James Edward Smith. Vol. 5, part II: "Class XXIV. Cryptogamia". London, England: Longman, Rees, Orme, Brown, Green & Longman. p. 7. From p. 7: "This has arisen, I conceive, partly from the practical difficulty of preserving specimens for the herbarium, partly from the absence of any general work, adapted to the immense advances which have of late years been made in the study of Mycology."
SSC. 2021. The IUCN Species Survival Commission calls for the due recognition of fungi as major components of biodiversity in legislation and policy. It fully endorses the Fauna Flora Funga Initiative and asks that the phrases animals and plants and fauna and flora be replaced with animals, fungi, and plants and fauna, flora, and funga.
^Berlin, Kustrim CerimiKustrim Cerimi studied biotechnology at the Technical University in; biotechnology, is currently doing his PhD He is interested in the broad field of fungal; Artists, Has Collaborated in Various Interdisciplinary Projects with; Artists, Hybrid (28 January 2022). "Mushroom meat substitutes: A brief patent overview". On Biology. Retrieved 25 May 2022.
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