Heterobasidion | |
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Heterobasidion annosum | |
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Genus: | Heterobasidion Bref. (1888) |
Type species | |
Heterobasidion annosum (Fr.) Bref. (1888) | |
Species | |
H. abietinum Contents |
Heterobasidion is a genus of basidiomycetes in the family of Bondarzewiaceae. Species in this genus include tree decay fungi that may be pathogenic and cause deterioration of tree health including mortality. Fungi in the genus produce shelf-like polyporous fruiting bodies that release spores from pores. Mating studies in the late twentieth century [1] and genetic studies in the early twenty-first century have led to description of several new species and replacement of some of the original names. [2] [3] As a result, two former Heterobasidion species, H. annosum and H. insulare , are now recognized to each comprise multiple distinct species.
Heterobasidion annosum sensu lato is a collection of the several species that cause Heterobasidion root disease and butt rot of forest trees and occasionally those in landscape plantings across the Northern Hemisphere. These fungi can be saprotrophic or necrotrophic, colonizing nonliving heartwood or living roots. Numerous tree species have been identified as hosts, but evergreen trees such as pine are most commonly affected. Heterobasidion root disease and butt rot are a serious issues to forest health due to tree mortality, decreased lumber volume and quality, and lessened carbon sequestration. [4] This group of species include some of the most intensively studied forest tree pathogens, becoming the first basidiomycete forest pathogen to have its genome sequenced in 2012. [5]
Heterobasidion annosum sensu lato includes five species, which differ in host preference, genetics, morphology, and geographic range. Sexual mating tests have identified three inter-sterility groups: P, S, and F, named after their chief hosts (pine, spruce, and fir). [1] [6] The five species are H. abietinum (F-type), H. annosum sensu stricto (P-type), H. irregulare (P-type), H. occidentale (S-type), and H. parviporum (S-type). Genetic analysis have demonstrated the North American species, H. irregulare and H. occidentale, are distinct from each other and the European species within their inter-sterility groups. [2]
The H. insulare complex comprises seven Heterobasidion species present in Eastern Asia and India. These are primarily saprotrophic decay fungi that are rarely pathogenic. These fungi are found on stumps and logs of are evergreen forest tree species including pines, firs, cedars, and spruces. Some species of this fungal complex can be easily differentiated from H. annosum sensu lato due to the red coloration on the top surface of the fruiting body.
Once considered a single species, the H. insulare complex is now considered to comprise six distinct species based on results of morphological studies, intersterility trials, and genetis. Mating tests have identified four inter-sterility groups: N, T, Y, and Z. [3] [7] The seven species are H. orientale (N-type), H. ecrustosum (T-type), H. insulare sensu typi, H. linzhiense, H. australe, H. amyloideum, H. tibeticum (Z-type). [3] [8] [9] [10]
Heterobasidion araucariae is a saprotrophic decay fungi found in Australia, Oceania, and may be present in Indochina. While not considered pathogenic it can help decay logs and stumps of Agathis , Araucaria , and Pine species. [11]
There are three isolates that have been proposed as new species but further description may be necessary.
The Russulales are an order of the Agaricomycetes,. According to the Dictionary of the Fungi, the order consists of 12 families, 80 genera, and 1767 species. According to Species Fungorum, the order contains 13 families, 117 genera, and 3,060 species.
The Polyporales are an order of about 1800 species of fungi in the division Basidiomycota. The order includes some polypores as well as many corticioid fungi and a few agarics. Many species within the order are saprotrophic, most of them wood-rotters. Some genera, such as Ganoderma and Fomes, contain species that attack living tissues and then continue to degrade the wood of their dead hosts. Those of economic importance include several important pathogens of forest and amenity trees and a few species that cause damage by rotting structural timber. Some of the Polyporales are commercially cultivated and marketed for use as food items or in traditional Chinese medicine.
Polypores are a group of fungi that form large fruiting bodies with pores or tubes on the underside. They are a morphological group of basidiomycetes-like gilled mushrooms and hydnoid fungi, and not all polypores are closely related to each other. Polypores are also called bracket fungi, and their woody fruiting bodies are called conks.
The Hymenochaetales are an order of fungi in the class Agaricomycetes. The order in its current sense is based on molecular research and not on any unifying morphological characteristics. According to one 2008 estimate, the Hymenochaetales contain around 600 species worldwide, mostly corticioid fungi and poroid fungi, but also including several clavarioid fungi and agarics. Species of economic importance include wood decay fungi in the genera Phellinus and Inonotus sensu lato, some of which may cause losses in forestry. Therapeutic properties are claimed for Inonotus obliquus ("chaga") and Phellinus linteus, both of which are now commercially marketed.
Saprotrophic nutrition or lysotrophic nutrition is a process of chemoheterotrophic extracellular digestion involved in the processing of decayed organic matter. It occurs in saprotrophs, and is most often associated with fungi and soil bacteria. Saprotrophic microscopic fungi are sometimes called saprobes; saprotrophic plants or bacterial flora are called saprophytes, though it is now believed that all plants previously thought to be saprotrophic are in fact parasites of microscopic fungi or other plants. The process is most often facilitated through the active transport of such materials through endocytosis within the internal mycelium and its constituent hyphae.
A wood-decay or xylophagous fungus is any species of fungus that digests moist wood, causing it to rot. Some species of wood-decay fungi attack dead wood, such as brown rot, and some, such as Armillaria, are parasitic and colonize living trees. Excessive moisture above the fibre saturation point in wood is required for fungal colonization and proliferation. Fungi that not only grow on wood but permeate its fibrous structure and actually cause decay, are called lignicolous fungi. In nature, this process causes the breakdown of complex molecules and leads to the return of nutrients to the soil. Various lignicolous fungi consume wood in various ways; for example, some attack the carbohydrates in wood and some others decay lignin. The rate of decay of wooden materials in various climates can be estimated by empirical models.
Heterobasidion annosum is a basidiomycete fungus in the family Bondarzewiaceae. It is considered to be the most economically important forest pathogen in the Northern Hemisphere. Heterobasidion annosum is widespread in forests in the United States and is responsible for the loss of one billion U.S. dollars annually. This fungus has been known by many different names. First described by Fries in 1821, it was known by the name Polyporus annosum. Later, it was found to be linked to conifer disease by Robert Hartig in 1874, and was renamed Fomes annosus by H. Karsten. Its current name of Heterobasidion annosum was given by Brefeld in 1888. Heterobasidion annosum causes one of the most destructive diseases of conifers. The disease caused by the fungus is named annosus root rot.
Stereum sanguinolentum is a species of fungus in the Stereaceae family. A plant pathogen, it causes red heart rot, a red discoloration on conifers, particularly spruces or Douglas-firs. Fruit bodies are produced on dead wood, or sometimes on dead branches of living trees. They are a thin leathery crust of the wood surface. Fresh fruit bodies will bleed a red-colored juice if injured, reflected in the common names bleeding Stereum or the bleeding conifer parchment. It can be the host of the parasitic jelly fungus Tremella encephala.
Oxyporus is a genus of polypore fungi in the family Schizoporaceae. An individual family Oxyporaceae was described for the genus. A number of species in this genus are plant pathogens, causing a white rot. The genus is widely distributed.
Turbinellus floccosus, commonly known as the scaly vase, or sometimes the shaggy, scaly, or woolly chanterelle, is a cantharelloid mushroom of the family Gomphaceae native to Asia and North America. It was known as Gomphus floccosus until 2011, when it was found to be only distantly related to the genus's type species, G. clavatus. It was consequently transferred from Gomphus to Turbinellus. The orange-capped vase- or trumpet-shaped fruiting bodies may reach 30 cm (12 in) high and 30 cm (12 in) wide. The lower surface, the hymenium, is covered in wrinkles and ridges rather than gills or pores, and is pale buff or yellowish to whitish.
Daedalea is a genus of fungi in the family Fomitopsidaceae. The genus was circumscribed in 1801 by mycologist Christian Hendrik Persoon, based on the type D. quercina and four other species. The generic name is derived from the Ancient Greek δαιδαλεος.
Antrodiella is a genus of fungi in the family Steccherinaceae of the order Polyporales.
Hartig net is a network of inward growing hyphae, that extends into the root, penetrating between the epidermis and cortex of ectomycorrhizal plants. This network is a site of nutrient exchange between the fungus and the host plant. The Hartig net is one of the three components required for ectomycorrhizal roots to form as part of ectomycorrhizal symbiosis with the host tree or plant.
Skeletocutis is a genus of about 40 species of poroid fungi in the family Polyporaceae. The genus has a cosmopolitan distribution, although most species are found in the Northern Hemisphere. Skeletocutis causes a white rot in a diverse array of woody substrates. Their fruit bodies grow as a crust on the surface of the decaying wood. Sometimes the edges of the crust are turned outward to form rudimentary bracket-like caps.
Kari Korhonen is a Finnish mycologist and forest pathologist, known for his studies of fungi causing root rot.
Heterobasidion irregulare is a tree root rotting pathogenic fungus that belongs to the genus Heterobasidion, which includes important pathogens of conifers and other woody plants. It has a wide host and geographic range throughout North America and causes considerable economic damage in pine plantations in the United States. This fungus is also a serious worry in eastern Canada. Heterobasidion irregulare has been introduced to Italy (Lazio)(modifica) where it has been responsible for extensive tree mortality of stone pine. Due to the ecology, disease type, host range/preference, interfertility group, and genetic information, H. irregulare was designated a new species and distinguished from Heterobasidion occidentale.
Hymenoscyphus albidus is a saprotrophic fungus which grows on the dead leaves of ash trees.
Heterobasidion occidentale is a tree root-rotting pathogenic fungus in the family Bondarzewiaceae. It is endemic in western North America west of the Rocky Mountains from Alaska to southern Mexico. While a natural agent of forest turnover, H. occidentale has become of increased concern due to forest management processes such as pre-commercial thinning, altered site density and species composition, and carbon sequestration. H. occidentale forms part of the genus that includes other species forming the important forest pest Heterobasidion annosumsensu lato that is spread across the Northern Hemisphere. H. occidentale is part of the S-type intersterility group differing from the other North American species, Heterobasidion irregulare.