Fungus

From Wikipedia for FEVERv2
Jump to navigation Jump to search

"Fungi" redirects here. Fungus_sentence_0

For other uses, see Fungi (disambiguation). Fungus_sentence_1

Fungus_table_infobox_0

Fungi

Temporal range: Early DevonianPresent (but see text) 410–0 Ma PreꞒ O S D C P T J K Pg NFungus_header_cell_0_0_0

Scientific classification FungiFungus_header_cell_0_1_0
(unranked):Fungus_cell_0_2_0 OpisthokontaFungus_cell_0_2_1
(unranked):Fungus_cell_0_3_0 HolomycotaFungus_cell_0_3_1
(unranked):Fungus_cell_0_4_0 ZoosporiaFungus_cell_0_4_1
Kingdom:Fungus_cell_0_5_0 Fungi

(L.) R.T.MooreFungus_cell_0_5_1

Subkingdoms/PhylaFungus_header_cell_0_6_0

A fungus (plural: fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. Fungus_sentence_2

These organisms are classified as a kingdom, which is separate from the other eukaryotic life kingdoms of plants and animals. Fungus_sentence_3

A characteristic that places fungi in a different kingdom from plants, bacteria, and some protists is chitin in their cell walls. Fungus_sentence_4

Similar to animals, fungi are heterotrophs; they acquire their food by absorbing dissolved molecules, typically by secreting digestive enzymes into their environment. Fungus_sentence_5

Fungi do not photosynthesize. Fungus_sentence_6

Growth is their means of mobility, except for spores (a few of which are flagellated), which may travel through the air or water. Fungus_sentence_7

Fungi are the principal decomposers in ecological systems. Fungus_sentence_8

These and other differences place fungi in a single group of related organisms, named the Eumycota (true fungi or Eumycetes), which share a common ancestor (from a monophyletic group), an interpretation that is also strongly supported by molecular phylogenetics. Fungus_sentence_9

This fungal group is distinct from the structurally similar myxomycetes (slime molds) and oomycetes (water molds). Fungus_sentence_10

The discipline of biology devoted to the study of fungi is known as mycology (from the Greek μύκης mykes, mushroom). Fungus_sentence_11

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. Fungus_sentence_12

Abundant worldwide, most fungi are inconspicuous because of the small size of their structures, and their cryptic lifestyles in soil or on dead matter. Fungus_sentence_13

Fungi include symbionts of plants, animals, or other fungi and also parasites. Fungus_sentence_14

They may become noticeable when fruiting, either as mushrooms or as molds. Fungus_sentence_15

Fungi perform an essential role in the decomposition of organic matter and have fundamental roles in nutrient cycling and exchange in the environment. Fungus_sentence_16

They have long been used as a direct source of human food, in the form of mushrooms and truffles; as a leavening agent for bread; and in the fermentation of various food products, such as wine, beer, and soy sauce. Fungus_sentence_17

Since the 1940s, fungi have been used for the production of antibiotics, and, more recently, various enzymes produced by fungi are used industrially and in detergents. Fungus_sentence_18

Fungi are also used as biological pesticides to control weeds, plant diseases and insect pests. Fungus_sentence_19

Many species produce bioactive compounds called mycotoxins, such as alkaloids and polyketides, that are toxic to animals including humans. Fungus_sentence_20

The fruiting structures of a few species contain psychotropic compounds and are consumed recreationally or in traditional spiritual ceremonies. Fungus_sentence_21

Fungi can break down manufactured materials and buildings, and become significant pathogens of humans and other animals. Fungus_sentence_22

Losses of crops due to fungal diseases (e.g., rice blast disease) or food spoilage can have a large impact on human food supplies and local economies. Fungus_sentence_23

The fungus kingdom encompasses an enormous diversity of taxa with varied ecologies, life cycle strategies, and morphologies ranging from unicellular aquatic chytrids to large mushrooms. Fungus_sentence_24

However, little is known of the true biodiversity of Kingdom Fungi, which has been estimated at 2.2 million to 3.8 million species. Fungus_sentence_25

Of these, only about 120,000 have been described, with over 8,000 species known to be detrimental to plants and at least 300 that can be pathogenic to humans. Fungus_sentence_26

Ever since the pioneering 18th and 19th century taxonomical works of Carl Linnaeus, Christian Hendrik Persoon, and Elias Magnus Fries, fungi have been classified according to their morphology (e.g., characteristics such as spore color or microscopic features) or physiology. Fungus_sentence_27

Advances in molecular genetics have opened the way for DNA analysis to be incorporated into taxonomy, which has sometimes challenged the historical groupings based on morphology and other traits. Fungus_sentence_28

Phylogenetic studies published in the first decade of the 21st century have helped reshape the classification within Kingdom Fungi, which is divided into one subkingdom, seven phyla, and ten subphyla. Fungus_sentence_29

Etymology Fungus_section_0

The English word fungus is directly adopted from the Latin fungus (mushroom), used in the writings of Horace and Pliny. Fungus_sentence_30

This in turn is derived from the Greek word sphongos (σφόγγος "sponge"), which refers to the macroscopic structures and morphology of mushrooms and molds; the root is also used in other languages, such as the German ("sponge") and ("mold"). Fungus_sentence_31

The word mycology is derived from the Greek mykes (μύκης "mushroom") and logos (λόγος "discourse"). Fungus_sentence_32

It denotes the scientific study of fungi. Fungus_sentence_33

The Latin adjectival form of "mycology" (mycologicæ) appeared as early as 1796 in a book on the subject by Christiaan Hendrik Persoon. Fungus_sentence_34

The word appeared in English as early as 1824 in a book by Robert Kaye Greville. Fungus_sentence_35

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. Fungus_sentence_36

A group of all the fungi present in a particular area or geographic region is known as mycobiota (plural noun, no singular), e.g., "the mycobiota of Ireland". Fungus_sentence_37

Characteristics Fungus_section_1

Before the introduction of molecular methods for phylogenetic analysis, taxonomists considered fungi to be members of the plant kingdom because of similarities in lifestyle: both fungi and plants are mainly immobile, and have similarities in general morphology and growth habitat. Fungus_sentence_38

Like plants, fungi often grow in soil and, in the case of mushrooms, form conspicuous fruit bodies, which sometimes resemble plants such as mosses. Fungus_sentence_39

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). Fungus_sentence_40

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: Fungus_sentence_41

Shared features: Fungus_sentence_42

Fungus_unordered_list_0

Unique features: Fungus_sentence_43

Fungus_unordered_list_1

  • Some species grow as unicellular yeasts that reproduce by budding or fission. Dimorphic fungi can switch between a yeast phase and a hyphal phase in response to environmental conditions.Fungus_item_1_6
  • The fungal cell wall is composed of glucans and chitin; while glucans are also found in plants and chitin in the exoskeleton of arthropods, 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.Fungus_item_1_7

Most fungi lack an efficient system for the long-distance transport of water and nutrients, such as the xylem and phloem in many plants. Fungus_sentence_44

To overcome this limitation, some fungi, such as Armillaria, form rhizomorphs, which resemble and perform functions similar to the roots of plants. Fungus_sentence_45

As eukaryotes, fungi possess a biosynthetic pathway for producing terpenes that uses mevalonic acid and pyrophosphate as chemical building blocks. Fungus_sentence_46

Plants and some other organisms have an additional terpene biosynthesis pathway in their chloroplasts, a structure fungi and animals do not have. Fungus_sentence_47

Fungi produce several secondary metabolites that are similar or identical in structure to those made by plants. Fungus_sentence_48

Many of the plant and fungal enzymes that make these compounds differ from each other in sequence and other characteristics, which indicates separate origins and convergent evolution of these enzymes in the fungi and plants. Fungus_sentence_49

Diversity Fungus_section_2

Fungi have a worldwide distribution, and grow in a wide range of habitats, including extreme environments such as deserts or areas with high salt concentrations or ionizing radiation, as well as in deep sea sediments. Fungus_sentence_50

Some can survive the intense UV and cosmic radiation encountered during space travel. Fungus_sentence_51

Most grow in terrestrial environments, though several species live partly or solely in aquatic habitats, such as the chytrid fungus Batrachochytrium dendrobatidis, a parasite that has been responsible for a worldwide decline in amphibian populations. Fungus_sentence_52

This organism spends part of its life cycle as a motile zoospore, enabling it to propel itself through water and enter its amphibian host. Fungus_sentence_53

Other examples of aquatic fungi include those living in hydrothermal areas of the ocean. Fungus_sentence_54

Around 120,000 species of fungi have been described by taxonomists, but the global biodiversity of the fungus kingdom is not fully understood. Fungus_sentence_55

A 2017 estimate suggests there may be between 2.2 and 3.8 million species. Fungus_sentence_56

In mycology, species have historically been distinguished by a variety of methods and concepts. Fungus_sentence_57

Classification based on morphological characteristics, such as the size and shape of spores or fruiting structures, has traditionally dominated fungal taxonomy. Fungus_sentence_58

Species may also be distinguished by their biochemical and physiological characteristics, such as their ability to metabolize certain biochemicals, or their reaction to chemical tests. Fungus_sentence_59

The biological species concept discriminates species based on their ability to mate. Fungus_sentence_60

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. Fungus_sentence_61

Mycology Fungus_section_3

Mycology is the branch of biology concerned with the systematic study of fungi, including their genetic and biochemical properties, their taxonomy, and their use to humans as a source of medicine, food, and psychotropic substances consumed for religious purposes, as well as their dangers, such as poisoning or infection. Fungus_sentence_62

The field of phytopathology, the study of plant diseases, is closely related because many plant pathogens are fungi. Fungus_sentence_63

The use of fungi by humans dates back to prehistory; Ötzi the Iceman, a well-preserved mummy of a 5,300-year-old Neolithic man found frozen in the Austrian Alps, carried two species of polypore mushrooms that may have been used as tinder (Fomes fomentarius), or for medicinal purposes (Piptoporus betulinus). Fungus_sentence_64

Ancient peoples have used fungi as food sources–often unknowingly–for millennia, in the preparation of leavened bread and fermented juices. Fungus_sentence_65

Some of the oldest written records contain references to the destruction of crops that were probably caused by pathogenic fungi. Fungus_sentence_66

History Fungus_section_4

Mycology is a relatively new science that became systematic after the development of the microscope in the 17th century. Fungus_sentence_67

Although fungal spores were first observed by Giambattista della Porta in 1588, the seminal work in the development of mycology is considered to be the publication of Pier Antonio Micheli's 1729 work Nova plantarum genera. Fungus_sentence_68

Micheli not only observed spores but also showed that, under the proper conditions, they could be induced into growing into the same species of fungi from which they originated. Fungus_sentence_69

Extending the use of the binomial system of nomenclature introduced by Carl Linnaeus in his Species plantarum (1753), the Dutch Christian Hendrik Persoon (1761–1836) established the first classification of mushrooms with such skill as to be considered a founder of modern mycology. Fungus_sentence_70

Later, Elias Magnus Fries (1794–1878) further elaborated the classification of fungi, using spore color and microscopic characteristics, methods still used by taxonomists today. Fungus_sentence_71

Other notable early contributors to mycology in the 17th–19th and early 20th centuries include Miles Joseph Berkeley, August Carl Joseph Corda, Anton de Bary, the brothers Louis René and Charles Tulasne, Arthur H. R. Buller, Curtis G. Lloyd, and Pier Andrea Saccardo. Fungus_sentence_72

In the 20th and 21st centuries, advances in biochemistry, genetics, molecular biology, biotechnology, DNA sequencing and phylogenetic analysis has provided new insights into fungal relationships and biodiversity, and has challenged traditional morphology-based groupings in fungal taxonomy. Fungus_sentence_73

Morphology Fungus_section_5

Microscopic structures Fungus_section_6

Most fungi grow as hyphae, which are cylindrical, thread-like structures 2–10 µm in diameter and up to several centimeters in length. Fungus_sentence_74

Hyphae grow at their tips (apices); new hyphae are typically formed by emergence of new tips along existing hyphae by a process called branching, or occasionally growing hyphal tips fork, giving rise to two parallel-growing hyphae. Fungus_sentence_75

Hyphae also sometimes fuse when they come into contact, a process called hyphal fusion (or anastomosis). Fungus_sentence_76

These growth processes lead to the development of a mycelium, an interconnected network of hyphae. Fungus_sentence_77

Hyphae can be either septate or coenocytic. Fungus_sentence_78

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. Fungus_sentence_79

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. Fungus_sentence_80

Coenocytic hyphae are in essence multinucleate supercells. Fungus_sentence_81

Many species have developed specialized hyphal structures for nutrient uptake from living hosts; examples include haustoria in plant-parasitic species of most fungal phyla, and arbuscules of several mycorrhizal fungi, which penetrate into the host cells to consume nutrients. Fungus_sentence_82

Although fungi are opisthokonts—a grouping of evolutionarily related organisms broadly characterized by a single posterior flagellum—all phyla except for the chytrids have lost their posterior flagella. Fungus_sentence_83

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. Fungus_sentence_84

Macroscopic structures Fungus_section_7

Fungal mycelia can become visible to the naked eye, for example, on various surfaces and substrates, such as damp walls and spoiled food, where they are commonly called molds. Fungus_sentence_85

Mycelia grown on solid agar media in laboratory petri dishes are usually referred to as colonies. Fungus_sentence_86

These colonies can exhibit growth shapes and colors (due to spores or pigmentation) that can be used as diagnostic features in the identification of species or groups. Fungus_sentence_87

Some individual fungal colonies can reach extraordinary dimensions and ages as in the case of a clonal colony of Armillaria solidipes, which extends over an area of more than 900 ha (3.5 square miles), with an estimated age of nearly 9,000 years. Fungus_sentence_88

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. Fungus_sentence_89

The fruit bodies of the basidiomycetes (basidiocarps) and some ascomycetes can sometimes grow very large, and many are well known as mushrooms. Fungus_sentence_90

Growth and physiology Fungus_section_8

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 surface area to volume ratios. Fungus_sentence_91

Hyphae are specifically adapted for growth on solid surfaces, and to invade substrates and tissues. Fungus_sentence_92

They can exert large penetrative mechanical forces; for example, many plant pathogens, including Magnaporthe grisea, form a structure called an appressorium that evolved to puncture plant tissues. Fungus_sentence_93

The pressure generated by the appressorium, directed against the plant epidermis, can exceed 8 megapascals (1,200 psi). Fungus_sentence_94

The filamentous fungus Paecilomyces lilacinus uses a similar structure to penetrate the eggs of nematodes. Fungus_sentence_95

The mechanical pressure exerted by the appressorium is generated from physiological processes that increase intracellular turgor by producing osmolytes such as glycerol. Fungus_sentence_96

Adaptations such as these are complemented by hydrolytic enzymes secreted into the environment to digest large organic molecules—such as polysaccharides, proteins, and lipids—into smaller molecules that may then be absorbed as nutrients. Fungus_sentence_97

The vast majority of filamentous fungi grow in a polar fashion (extending in one direction) by elongation at the tip (apex) of the hypha. Fungus_sentence_98

Other forms of fungal growth include intercalary extension (longitudinal expansion of hyphal compartments that are below the apex) as in the case of some endophytic fungi, or growth by volume expansion during the development of mushroom stipes and other large organs. Fungus_sentence_99

Growth of fungi as multicellular structures consisting of somatic and reproductive cells—a feature independently evolved in animals and plants—has several functions, including the development of fruit bodies for dissemination of sexual spores (see above) and biofilms for substrate colonization and intercellular communication. Fungus_sentence_100

The fungi are traditionally considered heterotrophs, organisms that rely solely on carbon fixed by other organisms for metabolism. Fungus_sentence_101

Fungi have evolved a high degree of metabolic versatility that allows them to use a diverse range of organic substrates for growth, including simple compounds such as nitrate, ammonia, acetate, or ethanol. Fungus_sentence_102

In some species the pigment melanin may play a role in extracting energy from ionizing radiation, such as gamma radiation. Fungus_sentence_103

This form of "radiotrophic" growth has been described for only a few species, the effects on growth rates are small, and the underlying biophysical and biochemical processes are not well known. Fungus_sentence_104

This process might bear similarity to CO2 fixation via visible light, but instead uses ionizing radiation as a source of energy. Fungus_sentence_105

Reproduction Fungus_section_9

Fungal reproduction is complex, reflecting the differences in lifestyles and genetic makeup within this diverse kingdom of organisms. Fungus_sentence_106

It is estimated that a third of all fungi reproduce using more than one method of propagation; for example, reproduction may occur in two well-differentiated stages within the life cycle of a species, the teleomorph and the anamorph. Fungus_sentence_107

Environmental conditions trigger genetically determined developmental states that lead to the creation of specialized structures for sexual or asexual reproduction. Fungus_sentence_108

These structures aid reproduction by efficiently dispersing spores or spore-containing propagules. Fungus_sentence_109

Asexual reproduction Fungus_section_10

Asexual reproduction occurs via vegetative spores (conidia) or through mycelial fragmentation. Fungus_sentence_110

Mycelial fragmentation occurs when a fungal mycelium separates into pieces, and each component grows into a separate mycelium. Fungus_sentence_111

Mycelial fragmentation and vegetative spores maintain clonal populations adapted to a specific niche, and allow more rapid dispersal than sexual reproduction. Fungus_sentence_112

The "Fungi imperfecti" (fungi lacking the perfect or sexual stage) or Deuteromycota comprise all the species that lack an observable sexual cycle. Fungus_sentence_113

Deuteromycota is not an accepted taxonomic clade, and is now taken to mean simply fungi that lack a known sexual stage. Fungus_sentence_114

Sexual reproduction Fungus_section_11

See also: Mating in fungi and Sexual selection in fungi Fungus_sentence_115

Sexual reproduction with meiosis has been directly observed in all fungal phyla except Glomeromycota (genetic analysis suggests meiosis in Glomeromycota as well). Fungus_sentence_116

It differs in many aspects from sexual reproduction in animals or plants. Fungus_sentence_117

Differences also exist between fungal groups and can be used to discriminate species by morphological differences in sexual structures and reproductive strategies. Fungus_sentence_118

Mating experiments between fungal isolates may identify species on the basis of biological species concepts. Fungus_sentence_119

The major fungal groupings have initially been delineated based on the morphology of their sexual structures and spores; for example, the spore-containing structures, asci and basidia, can be used in the identification of ascomycetes and basidiomycetes, respectively. Fungus_sentence_120

Fungi employ two mating systems: heterothallic species allow mating only between individuals of opposite mating type, whereas homothallic species can mate, and sexually reproduce, with any other individual or itself. Fungus_sentence_121

Most fungi have both a haploid and a diploid stage in their life cycles. Fungus_sentence_122

In sexually reproducing fungi, compatible individuals may combine by fusing their hyphae together into an interconnected network; this process, anastomosis, is required for the initiation of the sexual cycle. Fungus_sentence_123

Many ascomycetes and basidiomycetes go through a dikaryotic stage, in which the nuclei inherited from the two parents do not combine immediately after cell fusion, but remain separate in the hyphal cells (see heterokaryosis). Fungus_sentence_124

In ascomycetes, dikaryotic hyphae of the hymenium (the spore-bearing tissue layer) form a characteristic hook at the hyphal septum. Fungus_sentence_125

During cell division, formation of the hook ensures proper distribution of the newly divided nuclei into the apical and basal hyphal compartments. Fungus_sentence_126

An ascus (plural asci) is then formed, in which karyogamy (nuclear fusion) occurs. Fungus_sentence_127

Asci are embedded in an ascocarp, or fruiting body. Fungus_sentence_128

Karyogamy in the asci is followed immediately by meiosis and the production of ascospores. Fungus_sentence_129

After dispersal, the ascospores may germinate and form a new haploid mycelium. Fungus_sentence_130

Sexual reproduction in basidiomycetes is similar to that of the ascomycetes. Fungus_sentence_131

Compatible haploid hyphae fuse to produce a dikaryotic mycelium. Fungus_sentence_132

However, the dikaryotic phase is more extensive in the basidiomycetes, often also present in the vegetatively growing mycelium. Fungus_sentence_133

A specialized anatomical structure, called a clamp connection, is formed at each hyphal septum. Fungus_sentence_134

As with the structurally similar hook in the ascomycetes, the clamp connection in the basidiomycetes is required for controlled transfer of nuclei during cell division, to maintain the dikaryotic stage with two genetically different nuclei in each hyphal compartment. Fungus_sentence_135

A basidiocarp is formed in which club-like structures known as basidia generate haploid basidiospores after karyogamy and meiosis. Fungus_sentence_136

The most commonly known basidiocarps are mushrooms, but they may also take other forms (see Morphology section). Fungus_sentence_137

In fungi formerly classified as Zygomycota, haploid hyphae of two individuals fuse, forming a gametangium, a specialized cell structure that becomes a fertile gamete-producing cell. Fungus_sentence_138

The gametangium develops into a zygospore, a thick-walled spore formed by the union of gametes. Fungus_sentence_139

When the zygospore germinates, it undergoes meiosis, generating new haploid hyphae, which may then form asexual sporangiospores. Fungus_sentence_140

These sporangiospores allow the fungus to rapidly disperse and germinate into new genetically identical haploid fungal mycelia. Fungus_sentence_141

Spore dispersal Fungus_section_12

Both asexual and sexual spores or sporangiospores are often actively dispersed by forcible ejection from their reproductive structures. Fungus_sentence_142

This ejection ensures exit of the spores from the reproductive structures as well as traveling through the air over long distances. Fungus_sentence_143

Specialized mechanical and physiological mechanisms, as well as spore surface structures (such as hydrophobins), enable efficient spore ejection. Fungus_sentence_144

For example, the structure of the spore-bearing cells in some ascomycete species is such that the buildup of substances affecting cell volume and fluid balance enables the explosive discharge of spores into the air. Fungus_sentence_145

The forcible discharge of single spores termed ballistospores involves formation of a small drop of water (Buller's drop), which upon contact with the spore leads to its projectile release with an initial acceleration of more than 10,000 g; the net result is that the spore is ejected 0.01–0.02 cm, sufficient distance for it to fall through the gills or pores into the air below. Fungus_sentence_146

Other fungi, like the puffballs, rely on alternative mechanisms for spore release, such as external mechanical forces. Fungus_sentence_147

The hydnoid fungi (tooth fungi) produce spores on pendant, tooth-like or spine-like projections. Fungus_sentence_148

The bird's nest fungi use the force of falling water drops to liberate the spores from cup-shaped fruiting bodies. Fungus_sentence_149

Another strategy is seen in the stinkhorns, a group of fungi with lively colors and putrid odor that attract insects to disperse their spores. Fungus_sentence_150

Most of the researched species of fungus are transported by wind. Fungus_sentence_151

Such species often produce dry or hydrophobic spores which do not absorb water and are readily scattered by raindrops, for example. Fungus_sentence_152

Homothallism Fungus_section_13

In homothallic sexual reproduction, two haploid nuclei derived from the same individual fuse to form a zygote that can then undergo meiosis. Fungus_sentence_153

Homothallic fungi include species with an aspergillus-like asexual stage (anamorphs) occurring in numerous different genera, several species of the ascomycete genus Cochliobolus, and the ascomycete Pneumocystis jiroveccii. Fungus_sentence_154

Heitman reviewed evidence bearing on the evolution of sexual reproduction in the fungi and concluded that the earliest mode of sexual reproduction among eukaryotes was likely homothallism, that is, self-fertile unisexual reproduction. Fungus_sentence_155

Other sexual processes Fungus_section_14

Besides regular sexual reproduction with meiosis, certain fungi, such as those in the genera Penicillium and Aspergillus, may exchange genetic material via parasexual processes, initiated by anastomosis between hyphae and plasmogamy of fungal cells. Fungus_sentence_156

The frequency and relative importance of parasexual events is unclear and may be lower than other sexual processes. Fungus_sentence_157

It is known to play a role in intraspecific hybridization and is likely required for hybridization between species, which has been associated with major events in fungal evolution. Fungus_sentence_158

Evolution Fungus_section_15

Main article: Evolution of fungi Fungus_sentence_159

In contrast to plants and animals, the early fossil record of the fungi is meager. Fungus_sentence_160

Factors that likely contribute to the under-representation of fungal species among fossils include the nature of fungal fruiting bodies, which are soft, fleshy, and easily degradable tissues and the microscopic dimensions of most fungal structures, which therefore are not readily evident. Fungus_sentence_161

Fungal fossils are difficult to distinguish from those of other microbes, and are most easily identified when they resemble extant fungi. Fungus_sentence_162

Often recovered from a permineralized plant or animal host, these samples are typically studied by making thin-section preparations that can be examined with light microscopy or transmission electron microscopy. Fungus_sentence_163

Researchers study compression fossils by dissolving the surrounding matrix with acid and then using light or scanning electron microscopy to examine surface details. Fungus_sentence_164

The earliest fossils possessing features typical of fungi date to the Paleoproterozoic era, some  million years ago (Ma); these multicellular benthic organisms had filamentous structures capable of anastomosis. Fungus_sentence_165

Other studies (2009) estimate the arrival of fungal organisms at about 760–1060 Ma on the basis of comparisons of the rate of evolution in closely related groups. Fungus_sentence_166

For much of the Paleozoic Era (542–251 Ma), the fungi appear to have been aquatic and consisted of organisms similar to the extant chytrids in having flagellum-bearing spores. Fungus_sentence_167

The evolutionary adaptation from an aquatic to a terrestrial lifestyle necessitated a diversification of ecological strategies for obtaining nutrients, including parasitism, saprobism, and the development of mutualistic relationships such as mycorrhiza and lichenization. Fungus_sentence_168

Recent (2009) studies suggest that the ancestral ecological state of the Ascomycota was saprobism, and that independent lichenization events have occurred multiple times. Fungus_sentence_169

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. Fungus_sentence_170

Earlier, it had been presumed that the fungi colonized the land during the Cambrian (542–488.3 Ma), also long before land plants. Fungus_sentence_171

Fossilized hyphae and spores recovered from the Ordovician of Wisconsin (460 Ma) resemble modern-day Glomerales, and existed at a time when the land flora likely consisted of only non-vascular bryophyte-like plants. Fungus_sentence_172

Prototaxites, which was probably a fungus or lichen, would have been the tallest organism of the late Silurian and early Devonian. Fungus_sentence_173

Fungal fossils do not become common and uncontroversial until the early Devonian (416–359.2 Ma), when they occur abundantly in the Rhynie chert, mostly as Zygomycota and Chytridiomycota. Fungus_sentence_174

At about this same time, approximately 400 Ma, the Ascomycota and Basidiomycota diverged, and all modern classes of fungi were present by the Late Carboniferous (Pennsylvanian, 318.1–299 Ma). Fungus_sentence_175

Lichen-like fossils have been found in the Doushantuo Formation in southern China dating back to 635–551 Ma. Fungus_sentence_176

Lichens formed a component of the early terrestrial ecosystems, and the estimated age of the oldest terrestrial lichen fossil is 400 Ma; this date corresponds to the age of the oldest known sporocarp fossil, a Paleopyrenomycites species found in the Rhynie Chert. Fungus_sentence_177

The oldest fossil with microscopic features resembling modern-day basidiomycetes is Palaeoancistrus, found permineralized with a fern from the Pennsylvanian. Fungus_sentence_178

Rare in the fossil record are the Homobasidiomycetes (a taxon roughly equivalent to the mushroom-producing species of the Agaricomycetes). Fungus_sentence_179

Two amber-preserved specimens provide evidence that the earliest known mushroom-forming fungi (the extinct species Archaeomarasmius leggetti) appeared during the late Cretaceous, 90 Ma. Fungus_sentence_180

Some time after the Permian–Triassic extinction event (251.4 Ma), a fungal spike (originally thought to be an extraordinary abundance of fungal spores in sediments) formed, suggesting that fungi were the dominant life form at this time, representing nearly 100% of the available fossil record for this period. Fungus_sentence_181

However, the relative proportion of fungal spores relative to spores formed by algal species is difficult to assess, the spike did not appear worldwide, and in many places it did not fall on the Permian–Triassic boundary. Fungus_sentence_182

65 million years ago, immediately after the Cretaceous–Paleogene extinction event that famously killed off most dinosaurs, there is a dramatic increase in evidence of fungi, apparently the death of most plant and animal species leading to a huge fungal bloom like "a massive compost heap". Fungus_sentence_183

Taxonomy Fungus_section_16

Although commonly included in botany curricula and textbooks, fungi are more closely related to animals than to plants and are placed with the animals in the monophyletic group of opisthokonts. Fungus_sentence_184

Analyses using molecular phylogenetics support a monophyletic origin of fungi. Fungus_sentence_185

The taxonomy of fungi is in a state of constant flux, especially due to recent research based on DNA comparisons. Fungus_sentence_186

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. Fungus_sentence_187

There is no unique generally accepted system at the higher taxonomic levels and there are frequent name changes at every level, from species upwards. Fungus_sentence_188

Efforts among researchers are now underway to establish and encourage usage of a unified and more consistent nomenclature. Fungus_sentence_189

Fungal species can also have multiple scientific names depending on their life cycle and mode (sexual or asexual) of reproduction. Fungus_sentence_190

Web sites such as Index Fungorum and ITIS list current names of fungal species (with cross-references to older synonyms). Fungus_sentence_191

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. Fungus_sentence_192

It recognizes seven phyla, two of which—the Ascomycota and the Basidiomycota—are contained within a branch representing subkingdom Dikarya, the most species rich and familiar group, including all the mushrooms, most food-spoilage molds, most plant pathogenic fungi, and the beer, wine, and bread yeasts. Fungus_sentence_193

The accompanying cladogram depicts the major fungal taxa and their relationship to opisthokont and unikont organisms, based on the work of Philippe Silar, "The Mycota: A Comprehensive Treatise on Fungi as Experimental Systems for Basic and Applied Research" and Tedersoo et al. Fungus_sentence_194

2018. Fungus_sentence_195

The lengths of the branches are not proportional to evolutionary distances. Fungus_sentence_196

Taxonomic groups Fungus_section_17

See also: List of fungal orders Fungus_sentence_197

The major phyla (sometimes called divisions) of fungi have been classified mainly on the basis of characteristics of their sexual reproductive structures. Fungus_sentence_198

Currently, seven phyla are proposed: Microsporidia, Chytridiomycota, Blastocladiomycota, Neocallimastigomycota, Glomeromycota, Ascomycota, and Basidiomycota. Fungus_sentence_199

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). Fungus_sentence_200

One 2006 study concludes that the Microsporidia are a sister group to the true fungi; that is, they are each other's closest evolutionary relative. Fungus_sentence_201

Hibbett and colleagues suggest that this analysis does not clash with their classification of the Fungi, and although the Microsporidia are elevated to phylum status, it is acknowledged that further analysis is required to clarify evolutionary relationships within this group. Fungus_sentence_202

The Chytridiomycota are commonly known as chytrids. Fungus_sentence_203

These fungi are distributed worldwide. Fungus_sentence_204

Chytrids and their close relatives Neocallimastigomycota and Blastocladiomycota (below) are the only fungi with active motility, producing zoospores that are capable of active movement through aqueous phases with a single flagellum, leading early taxonomists to classify them as protists. Fungus_sentence_205

Molecular phylogenies, inferred from 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. Fungus_sentence_206

The Blastocladiomycota were previously considered a taxonomic clade within the Chytridiomycota. Fungus_sentence_207

Recent molecular data and ultrastructural characteristics, however, place the Blastocladiomycota as a sister clade to the Zygomycota, Glomeromycota, and Dikarya (Ascomycota and Basidiomycota). Fungus_sentence_208

The blastocladiomycetes are saprotrophs, feeding on decomposing organic matter, and they are parasites of all eukaryotic groups. Fungus_sentence_209

Unlike their close relatives, the chytrids, most of which exhibit zygotic meiosis, the blastocladiomycetes undergo sporic meiosis. Fungus_sentence_210

The Neocallimastigomycota were earlier placed in the phylum Chytridomycota. Fungus_sentence_211

Members of this small phylum are anaerobic organisms, living in the digestive system of larger herbivorous mammals and in other terrestrial and aquatic environments enriched in cellulose (e.g., domestic waste landfill sites). Fungus_sentence_212

They lack mitochondria but contain hydrogenosomes of mitochondrial origin. Fungus_sentence_213

As in the related chrytrids, neocallimastigomycetes form zoospores that are posteriorly uniflagellate or polyflagellate. Fungus_sentence_214

Members of the Glomeromycota form arbuscular mycorrhizae, a form of mutualist symbiosis wherein fungal hyphae invade plant root cells and both species benefit from the resulting increased supply of nutrients. Fungus_sentence_215

All known Glomeromycota species reproduce asexually. Fungus_sentence_216

The symbiotic association between the Glomeromycota and plants is ancient, with evidence dating to 400 million years ago. Fungus_sentence_217

Formerly part of the Zygomycota (commonly known as 'sugar' and 'pin' molds), the Glomeromycota were elevated to phylum status in 2001 and now replace the older phylum Zygomycota. Fungus_sentence_218

Fungi that were placed in the Zygomycota are now being reassigned to the Glomeromycota, or the subphyla incertae sedis Mucoromycotina, Kickxellomycotina, the Zoopagomycotina and the Entomophthoromycotina. Fungus_sentence_219

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. Fungus_sentence_220

Medically relevant genera include Mucor, Rhizomucor, and Rhizopus. Fungus_sentence_221

The Ascomycota, commonly known as sac fungi or ascomycetes, constitute the largest taxonomic group within the Eumycota. Fungus_sentence_222

These fungi form meiotic spores called ascospores, which are enclosed in a special sac-like structure called an ascus. Fungus_sentence_223

This phylum includes morels, a few mushrooms and truffles, unicellular yeasts (e.g., of the genera Saccharomyces, Kluyveromyces, Pichia, and Candida), and many filamentous fungi living as saprotrophs, parasites, and mutualistic symbionts (e.g. lichens). Fungus_sentence_224

Prominent and important genera of filamentous ascomycetes include Aspergillus, Penicillium, Fusarium, and Claviceps. Fungus_sentence_225

Many ascomycete species have only been observed undergoing asexual reproduction (called anamorphic species), but analysis of molecular data has often been able to identify their closest teleomorphs in the Ascomycota. Fungus_sentence_226

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). Fungus_sentence_227

Members of the Basidiomycota, commonly known as the club fungi or basidiomycetes, produce meiospores called basidiospores on club-like stalks called basidia. Fungus_sentence_228

Most common mushrooms belong to this group, as well as rust and smut fungi, which are major pathogens of grains. Fungus_sentence_229

Other important basidiomycetes include the maize pathogen Ustilago maydis, human commensal species of the genus Malassezia, and the opportunistic human pathogen, Cryptococcus neoformans. Fungus_sentence_230

Fungus-like organisms Fungus_section_18

Because of similarities in morphology and lifestyle, the slime molds (mycetozoans, plasmodiophorids, acrasids, Fonticula and labyrinthulids, now in Amoebozoa, Rhizaria, Excavata, Opisthokonta and Stramenopiles, respectively), water molds (oomycetes) and hyphochytrids (both Stramenopiles) were formerly classified in the kingdom Fungi, in groups like Mastigomycotina, Gymnomycota and Phycomycetes. Fungus_sentence_231

The slime molds were studied also as protozoans, leading to an ambiregnal, duplicated taxonomy. Fungus_sentence_232

Unlike true fungi, the cell walls of oomycetes contain cellulose and lack chitin. Fungus_sentence_233

Hyphochytrids have both chitin and cellulose. Fungus_sentence_234

Slime molds lack a cell wall during the assimilative phase (except labyrinthulids, which have a wall of scales), and ingest nutrients by ingestion (phagocytosis, except labyrinthulids) rather than absorption (osmotrophy, as fungi, labyrinthulids, oomycetes and hyphochytrids). Fungus_sentence_235

Neither water molds nor slime molds are closely related to the true fungi, and, therefore, taxonomists no longer group them in the kingdom Fungi. Fungus_sentence_236

Nonetheless, studies of the oomycetes and myxomycetes are still often included in mycology textbooks and primary research literature. Fungus_sentence_237

The Eccrinales and Amoebidiales are opisthokont protists, previously thought to be zygomycete fungi. Fungus_sentence_238

Other groups now in Opisthokonta (e.g., Corallochytrium, Ichthyosporea) were also at given time classified as fungi. Fungus_sentence_239

The genus Blastocystis, now in Stramenopiles, was originally classified as a yeast. Fungus_sentence_240

Ellobiopsis, now in Alveolata, was considered a chytrid. Fungus_sentence_241

The bacteria were also included in fungi in some classifications, as the group Schizomycetes. Fungus_sentence_242

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. Fungus_sentence_243

Members of the group that have been isolated lack the chitinous cell wall that is characteristic of fungi. Fungus_sentence_244

The nucleariids may be the next sister group to the eumycete clade, and as such could be included in an expanded fungal kingdom. Fungus_sentence_245

Many Actinomycetales (Actinobacteria), a group with many filamentous bacteria, were also long believed to be fungi. Fungus_sentence_246

Ecology Fungus_section_19

Although often inconspicuous, fungi occur in every environment on Earth and play very important roles in most ecosystems. Fungus_sentence_247

Along with bacteria, fungi are the major decomposers in most terrestrial (and some aquatic) ecosystems, and therefore play a critical role in biogeochemical cycles and in many food webs. Fungus_sentence_248

As decomposers, they play an essential role in nutrient cycling, especially as saprotrophs and symbionts, degrading organic matter to inorganic molecules, which can then re-enter anabolic metabolic pathways in plants or other organisms. Fungus_sentence_249

Symbiosis Fungus_section_20

Many fungi have important symbiotic relationships with organisms from most if not all kingdoms. Fungus_sentence_250

These interactions can be mutualistic or antagonistic in nature, or in the case of commensal fungi are of no apparent benefit or detriment to the host. Fungus_sentence_251

With plants Fungus_section_21

Mycorrhizal symbiosis between 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. Fungus_sentence_252

The mycorrhizal symbiosis is ancient, dating back to at least 400 million years. Fungus_sentence_253

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. Fungus_sentence_254

The fungal partners may also mediate plant-to-plant transfer of carbohydrates and other nutrients. Fungus_sentence_255

Such mycorrhizal communities are called "common mycorrhizal networks". Fungus_sentence_256

A special case of mycorrhiza is myco-heterotrophy, whereby the plant parasitizes the fungus, obtaining all of its nutrients from its fungal symbiont. Fungus_sentence_257

Some fungal species inhabit the tissues inside roots, stems, and leaves, in which case they are called endophytes. Fungus_sentence_258

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. Fungus_sentence_259

With algae and cyanobacteria Fungus_section_22

Lichens are a symbiotic relationship between fungi and photosynthetic algae or cyanobacteria. Fungus_sentence_260

The photosynthetic partner in the relationship is referred to in lichen terminology as a "photobiont". Fungus_sentence_261

The fungal part of the relationship is composed mostly of various species of ascomycetes and a few basidiomycetes. Fungus_sentence_262

Lichens occur in every ecosystem on all continents, play a key role in soil formation and the initiation of biological succession, and are prominent in some extreme environments, including polar, alpine, and semiarid desert regions. Fungus_sentence_263

They are able to grow on inhospitable surfaces, including bare soil, rocks, tree bark, wood, shells, barnacles and leaves. Fungus_sentence_264

As in mycorrhizas, the photobiont provides sugars and other carbohydrates via photosynthesis to the fungus, while the fungus provides minerals and water to the photobiont. Fungus_sentence_265

The functions of both symbiotic organisms are so closely intertwined that they function almost as a single organism; in most cases the resulting organism differs greatly from the individual components. Fungus_sentence_266

Lichenization is a common mode of nutrition for fungi; around 20% of fungi—between 17,500 and 20,000 described species—are lichenized. Fungus_sentence_267

Characteristics common to most lichens include obtaining 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. Fungus_sentence_268

With insects Fungus_section_23

Many insects also engage in mutualistic relationships with fungi. Fungus_sentence_269

Several groups of ants cultivate fungi in the order Agaricales as their primary food source, while ambrosia beetles cultivate various species of fungi in the bark of trees that they infest. Fungus_sentence_270

Likewise, females of several wood wasp species (genus Sirex) inject their eggs together with spores of the wood-rotting fungus Amylostereum areolatum into the sapwood of pine trees; the growth of the fungus provides ideal nutritional conditions for the development of the wasp larvae. Fungus_sentence_271

At least one species of stingless bee has a relationship with a fungus in the genus Monascus, where the larvae consume and depend on fungus transferred from old to new nests. Fungus_sentence_272

Termites on the African savannah are also known to cultivate fungi, and yeasts of the genera Candida and Lachancea inhabit the gut of a wide range of insects, including neuropterans, beetles, and cockroaches; it is not known whether these fungi benefit their hosts. Fungus_sentence_273

Fungi ingrowing dead wood are essential for xylophagous insects (e.g. woodboring beetles). Fungus_sentence_274

They deliver nutrients needed by xylophages to nutritionally scarce dead wood. Fungus_sentence_275

Thanks to this nutritional enrichment the larvae of woodboring insect is able to grow and develop to adulthood. Fungus_sentence_276

The larvae of many families of fungicolous flies, particularly those within the superfamily Sciaroidea such as the Mycetophilidae and some Keroplatidae feed on fungal fruiting bodies and sterile mycorrhizae. Fungus_sentence_277

As pathogens and parasites Fungus_section_24

Many fungi are parasites on plants, animals (including humans), and other fungi. Fungus_sentence_278

Serious pathogens of many cultivated plants causing extensive damage and losses to agriculture and forestry include the rice blast fungus Magnaporthe oryzae, tree pathogens such as Ophiostoma ulmi and Ophiostoma novo-ulmi causing Dutch elm disease and Cryphonectria parasitica responsible for chestnut blight, and plant pathogens in the genera Fusarium, Ustilago, Alternaria, and Cochliobolus. Fungus_sentence_279

Some carnivorous fungi, like Paecilomyces lilacinus, are predators of nematodes, which they capture using an array of specialized structures such as constricting rings or adhesive nets. Fungus_sentence_280

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). Fungus_sentence_281

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. Fungus_sentence_282

Some fungi can cause serious diseases in humans, several of which may be fatal if untreated. Fungus_sentence_283

These include aspergillosis, candidiasis, coccidioidomycosis, cryptococcosis, histoplasmosis, mycetomas, and paracoccidioidomycosis. Fungus_sentence_284

Furthermore, persons with immuno-deficiencies are particularly susceptible to disease by genera such as Aspergillus, Candida, Cryptoccocus, Histoplasma, and Pneumocystis. Fungus_sentence_285

Other fungi can attack eyes, nails, hair, and especially skin, the so-called dermatophytic and keratinophilic fungi, and cause local infections such as ringworm and athlete's foot. Fungus_sentence_286

Fungal spores are also a cause of allergies, and fungi from different taxonomic groups can evoke allergic reactions. Fungus_sentence_287

As targets of mycoparasites Fungus_section_25

The organisms which parasitize fungi are known as mycoparasitic organisms. Fungus_sentence_288

Certain species of the genus Pythium, which are oomycetes, have potential as biocontrol agents against certain fungi. Fungus_sentence_289

Fungi can also act as mycoparasites or antagonists of other fungi, such as Hypomyces chrysospermus, which grows on bolete mushrooms. Fungus_sentence_290

Fungi can also become the target of infection by mycoviruses. Fungus_sentence_291

Mycotoxins Fungus_section_26

Many fungi produce biologically active compounds, several of which are toxic to animals or plants and are therefore called mycotoxins. Fungus_sentence_292

Of particular relevance to humans are mycotoxins produced by molds causing food spoilage, and poisonous mushrooms (see above). Fungus_sentence_293

Particularly infamous are the lethal amatoxins in some Amanita mushrooms, and ergot alkaloids, which have a long history of causing serious epidemics of ergotism (St Anthony's Fire) in people consuming rye or related cereals contaminated with sclerotia of the ergot fungus, Claviceps purpurea. Fungus_sentence_294

Other notable mycotoxins include the aflatoxins, which are insidious liver toxins and highly carcinogenic metabolites produced by certain Aspergillus species often growing in or on grains and nuts consumed by humans, ochratoxins, patulin, and trichothecenes (e.g., T-2 mycotoxin) and fumonisins, which have significant impact on human food supplies or animal livestock. Fungus_sentence_295

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. Fungus_sentence_296

Mycotoxins may provide fitness benefits in terms of physiological adaptation, competition with other microbes and fungi, and protection from consumption (fungivory). Fungus_sentence_297

Many fungal secondary metabolites (or derivatives) are used medically, as described under Human Use below. Fungus_sentence_298

Pathogenic mechanisms Fungus_section_27

Ustilago maydis is a pathogenic plant fungus that causes smut disease in maize and teosinte. Fungus_sentence_299

Plants have evolved efficient defense systems against pathogenic microbes such as U. maydis. Fungus_sentence_300

A rapid defense reaction after pathogen attack is the oxidative burst where the plant produces reactive oxygen species at the site of the attempted invasion. Fungus_sentence_301

U. maydis can respond to the oxidative burst with an oxidative stress response, regulated by the gene YAP1. Fungus_sentence_302

The response protects U. maydis from the host defense, and is necessary for the pathogen's virulence. Fungus_sentence_303

Furthermore, U. maydis has a well-established recombinational DNA repair system which acts during mitosis and meiosis. Fungus_sentence_304

The system may assist the pathogen in surviving DNA damage arising from the host plant's oxidative defensive response to infection. Fungus_sentence_305

Cryptococcus neoformans is an encapsulated yeast that can live in both plants and animals. Fungus_sentence_306

C. neoformans usually infects the lungs, where it is phagocytosed by alveolar macrophages. Fungus_sentence_307

Some C. neoformans can survive inside macrophages, which appears to be the basis for latency, disseminated disease, and resistance to antifungal agents. Fungus_sentence_308

One mechanism by which C. neoformans survives the hostile macrophage environment is by up-regulating the expression of genes involved in the oxidative stress response. Fungus_sentence_309

Another mechanism involves meiosis. Fungus_sentence_310

The majority of C. neoformans are mating "type a". Fungus_sentence_311

Filaments of mating "type a" ordinarily have haploid nuclei, but they can become diploid (perhaps by endoduplication or by stimulated nuclear fusion) to form blastospores. Fungus_sentence_312

The diploid nuclei of blastospores can undergo meiosis, including recombination, to form haploid basidiospores that can be dispersed. Fungus_sentence_313

This process is referred to as monokaryotic fruiting. Fungus_sentence_314

This process requires a gene called 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. Fungus_sentence_315

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. Fungus_sentence_316

Human use Fungus_section_28

The human use of fungi for food preparation or preservation and other purposes is extensive and has a long history. Fungus_sentence_317

Mushroom farming and mushroom gathering are large industries in many countries. Fungus_sentence_318

The study of the historical uses and sociological impact of fungi is known as ethnomycology. Fungus_sentence_319

Because of the capacity of this group to produce an enormous range of natural products with antimicrobial or other biological activities, many species have long been used or are being developed for industrial production of antibiotics, vitamins, and anti-cancer and cholesterol-lowering drugs. Fungus_sentence_320

More recently, methods have been developed for genetic engineering of fungi, enabling metabolic engineering of fungal species. Fungus_sentence_321

For example, genetic modification of yeast species—which are easy to grow at fast rates in large fermentation vessels—has opened up ways of pharmaceutical production that are potentially more efficient than production by the original source organisms. Fungus_sentence_322

Therapeutic uses Fungus_section_29

Modern chemotherapeutics Fungus_section_30

See also: Medicinal fungi Fungus_sentence_323

Many species produce metabolites that are major sources of pharmacologically active drugs. Fungus_sentence_324

Particularly important are the antibiotics, including the penicillins, a structurally related group of β-lactam antibiotics that are synthesized from small peptides. Fungus_sentence_325

Although naturally occurring penicillins such as penicillin G (produced by Penicillium chrysogenum) have a relatively narrow spectrum of biological activity, a wide range of other penicillins can be produced by chemical modification of the natural penicillins. Fungus_sentence_326

Modern penicillins are semisynthetic compounds, obtained initially from fermentation cultures, but then structurally altered for specific desirable properties. Fungus_sentence_327

Other antibiotics produced by fungi include: ciclosporin, commonly used as an immunosuppressant during transplant surgery; and fusidic acid, used to help control infection from methicillin-resistant Staphylococcus aureus bacteria. Fungus_sentence_328

Widespread use of antibiotics for the treatment of bacterial diseases, such as tuberculosis, syphilis, leprosy, and others began in the early 20th century and continues to date. Fungus_sentence_329

In nature, antibiotics of fungal or bacterial origin appear to play a dual role: at high concentrations they act as chemical defense against competition with other microorganisms in species-rich environments, such as the rhizosphere, and at low concentrations as quorum-sensing molecules for intra- or interspecies signaling. Fungus_sentence_330

Other drugs produced by fungi include griseofulvin isolated from Penicillium griseofulvum, used to treat fungal infections, and statins (HMG-CoA reductase inhibitors), used to inhibit cholesterol synthesis. Fungus_sentence_331

Examples of statins found in fungi include mevastatin from Penicillium citrinum and lovastatin from Aspergillus terreus and the oyster mushroom. Fungus_sentence_332

Fungi produce compounds that inhibit viruses and cancer cells. Fungus_sentence_333

Specific metabolites, such as polysaccharide-K, ergotamine, and β-lactam antibiotics, are routinely used in clinical medicine. Fungus_sentence_334

The shiitake mushroom is a source of lentinan, a clinical drug approved for use in cancer treatments in several countries, including Japan. Fungus_sentence_335

In Europe and Japan, polysaccharide-K (brand name Krestin), a chemical derived from Trametes versicolor, is an approved adjuvant for cancer therapy. Fungus_sentence_336

Traditional and folk medicine Fungus_section_31

Certain mushrooms enjoy usage as therapeutics in folk medicines, such as Traditional Chinese medicine. Fungus_sentence_337

Notable medicinal mushrooms with a well-documented history of use include Agaricus subrufescens, Ganoderma lucidum, Psilocybe and Ophiocordyceps sinensis. Fungus_sentence_338

Cultured foods Fungus_section_32

Baker's yeast or Saccharomyces cerevisiae, a unicellular fungus, is used to make bread and other wheat-based products, such as pizza dough and dumplings. Fungus_sentence_339

Yeast species of the genus Saccharomyces are also used to produce alcoholic beverages through fermentation. Fungus_sentence_340

Shoyu koji mold (Aspergillus oryzae) is an essential ingredient in brewing Shoyu (soy sauce) and sake, and the preparation of miso, while Rhizopus species are used for making tempeh. Fungus_sentence_341

Several of these fungi are domesticated species that were bred or selected according to their capacity to ferment food without producing harmful mycotoxins (see below), which are produced by very closely related Aspergilli. Fungus_sentence_342

Quorn, a meat substitute, is made from Fusarium venenatum. Fungus_sentence_343

In food Fungus_section_33

Edible mushrooms include commercially raised and wild-harvested fungi. Fungus_sentence_344

Agaricus bisporus, sold as button mushrooms when small or Portobello mushrooms when larger, is the most widely cultivated species in the West, used in salads, soups, and many other dishes. Fungus_sentence_345

Many Asian fungi are commercially grown and have increased in popularity in the West. Fungus_sentence_346

They are often available fresh in grocery stores and markets, including straw mushrooms (Volvariella volvacea), oyster mushrooms (Pleurotus ostreatus), shiitakes (Lentinula edodes), and enokitake (Flammulina spp.). Fungus_sentence_347

Many other mushroom species are harvested from the wild for personal consumption or commercial sale. Fungus_sentence_348

Milk mushrooms, morels, chanterelles, truffles, black trumpets, and porcini mushrooms (Boletus edulis) (also known as king boletes) demand a high price on the market. Fungus_sentence_349

They are often used in gourmet dishes. Fungus_sentence_350

Certain types of cheeses require inoculation of milk curds with fungal species that impart a unique flavor and texture to the cheese. Fungus_sentence_351

Examples include the blue color in cheeses such as Stilton or Roquefort, which are made by inoculation with Penicillium roqueforti. Fungus_sentence_352

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. Fungus_sentence_353

Poisonous fungi Fungus_section_34

Many mushroom species are poisonous to humans and cause a range of reactions including slight digestive problems, allergic reactions, hallucinations, severe organ failure, and death. Fungus_sentence_354

Genera with mushrooms containing deadly toxins include Conocybe, Galerina, Lepiota, and, the most infamous, Amanita. Fungus_sentence_355

The latter genus includes the destroying angel (A. Fungus_sentence_356 virosa) and the death cap (A. Fungus_sentence_357 phalloides), the most common cause of deadly mushroom poisoning. Fungus_sentence_358

The false morel (Gyromitra esculenta) is occasionally considered a delicacy when cooked, yet can be highly toxic when eaten raw. Fungus_sentence_359

Tricholoma equestre was considered edible until it was implicated in serious poisonings causing rhabdomyolysis. Fungus_sentence_360

Fly agaric mushrooms (Amanita muscaria) also cause occasional non-fatal poisonings, mostly as a result of ingestion for its hallucinogenic properties. Fungus_sentence_361

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. Fungus_sentence_362

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. Fungus_sentence_363

Pest control Fungus_section_35

In agriculture, fungi may be useful if they actively compete for nutrients and space with pathogenic microorganisms such as bacteria or other fungi via the competitive exclusion principle, or if they are parasites of these pathogens. Fungus_sentence_364

For example, certain species may be used to eliminate or suppress the growth of harmful plant pathogens, such as insects, mites, weeds, nematodes, and other fungi that cause diseases of important crop plants. Fungus_sentence_365

This has generated strong interest in practical applications that use these fungi in the biological control of these agricultural pests. Fungus_sentence_366

Entomopathogenic fungi can be used as biopesticides, as they actively kill insects. Fungus_sentence_367

Examples that have been used as biological insecticides are Beauveria bassiana, Metarhizium spp, Hirsutella spp, Paecilomyces (Isaria) spp, and Lecanicillium lecanii. Fungus_sentence_368

Endophytic fungi of grasses of the genus Neotyphodium, such as N. Fungus_sentence_369 coenophialum, produce alkaloids that are toxic to a range of invertebrate and vertebrate herbivores. Fungus_sentence_370

These alkaloids protect grass plants from herbivory, but several endophyte alkaloids can poison grazing animals, such as cattle and sheep. Fungus_sentence_371

Infecting cultivars of pasture or forage grasses with Neotyphodium 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. Fungus_sentence_372

Bioremediation Fungus_section_36

See also: Mycoremediation Fungus_sentence_373

Certain fungi, in particular white-rot fungi, can degrade insecticides, herbicides, pentachlorophenol, creosote, coal tars, and heavy fuels and turn them into carbon dioxide, water, and basic elements. Fungus_sentence_374

Fungi have been shown to biomineralize uranium oxides, suggesting they may have application in the bioremediation of radioactively polluted sites. Fungus_sentence_375

Model organisms Fungus_section_37

Several pivotal discoveries in biology were made by researchers using fungi as model organisms, that is, fungi that grow and sexually reproduce rapidly in the laboratory. Fungus_sentence_376

For example, the one gene-one enzyme hypothesis was formulated by scientists using the bread mold Neurospora crassa to test their biochemical theories. Fungus_sentence_377

Other important model fungi are Aspergillus nidulans and the yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe, each of which with a long history of use to investigate issues in eukaryotic cell biology and genetics, such as cell cycle regulation, chromatin structure, and gene regulation. Fungus_sentence_378

Other fungal models have more recently emerged that address specific biological questions relevant to medicine, plant pathology, and industrial uses; examples include Candida albicans, a dimorphic, opportunistic human pathogen, Magnaporthe grisea, a plant pathogen, and Pichia pastoris, a yeast widely used for eukaryotic protein production. Fungus_sentence_379

Others Fungus_section_38

Fungi are used extensively to produce industrial chemicals like citric, gluconic, lactic, and malic acids, and industrial enzymes, such as lipases used in biological detergents, cellulases used in making cellulosic ethanol and stonewashed jeans, and amylases, invertases, proteases and xylanases. Fungus_sentence_380

See also Fungus_section_39

Credits to the contents of this page go to the authors of the corresponding Wikipedia page: en.wikipedia.org/wiki/Fungus.