Basidiomycetes [2] , or basidiomycetes , or basidiomycota [3] ( lat. Basidiomycota ) - a department from the kingdom of mushrooms , including species that produce spores in the club-shaped structures called basidia . Together with the ascomycetes, they make up the subdomain of higher mushrooms ( Dikarya ).
| Basidiomycetes | |||||||||
 Lepista glaucocana | |||||||||
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Basidiomycota RT Moore , 1980 | |||||||||
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Content
Features
Mycelium
The mycelium of basidiomycetes is septic, each cell contains two haploid nuclei . Usually the nuclei are located near the middle of the cell; their pair is called the dicarion . Near the septum on the hyphae of most basidiomycetes, a buckle is formed that participates in cell division. A buckle is a thin outgrowth from one cell of a fungus adjacent to another neighboring cell. When dividing, the nucleus cells synchronously double and the buckle allows the nuclei formed from different initial nuclei to be in the same cell.
Life Cycle
Asexual reproduction of basidiomycetes is carried out by conidia , but rarely occurs. Sexual reproduction occurs in the form of somatogamy , in which two vegetative mononuclear haploid mycelium cells merge. In a small number of homotallic species, cells of the same mycelium can merge. Most species are heterotallic; accordingly, somatogamy occurs only between hyphae with opposite signs “+” and “-”. Genital organs in basidiomycetes do not form.
As with ascomycetes , plasmogamy, i.e., fusion of the cytoplasm of the cells, follows first. The haploid nuclei come together, forming a dicarion, but do not merge with each other. Cells can divide in this case - at the same time, both nuclei of the dicarion are mitotically divided. As a result, each hyphal cell contains a dicarion. In most species, cell division is accompanied by the formation of lateral outgrowths - buckles , which ensure equal division of sister nuclei and their distribution into daughter cells. The stage of the dicarion is very long, it can last for years (for some tinder men for decades). At the same time, mycelium grows, penetrating the substrate . Dicarions, in addition, can form when the conidia are transferred to the mycelium of the opposite sign. In some species (for example, in smut species ), basidiospores may merge.
The organs of sexual sporulation - basidiospores - develop exogenously in special structures - basidia . In this case, karyogamy occurs - the fusion of the nuclei of the dicarion, and a zygote is formed, which without merit is divided meiotically . The four haploid cells formed in this process become basidiospores, and the cell from which they arose is basidium. Basidiospores are usually located on small and thin outgrowths of basidia - sterigm .
Depending on the structure, several types of basidia are distinguished. Holobasidia are club-shaped and have a unicellular structure. Heterobazidia consist of an expanded lower part - hypobasidia and upper - epibazidia , which is an outgrowth of hypobasidia. Phragmobasidia , or teliobasidia , are formed from a thick-walled resting cell by the formation of transverse septa dividing it into four cells. Basidiospores develop on the sides of these cells.
In primitive forms, basidia are formed at the ends of dicarionic hyphae without the formation of a fruiting body. However, in most species of basidiomycetes, basidia are formed on fruiting bodies in the hymenial layer. In addition to basidia, there are sterile hyphae there - paraphyses ( dr. Greek παρα- “near”, φῦσα - “bloating”), and in some forms there are still large cells - cystids, which rise above the spore-bearing layer and protect it. The entire surface of the fruiting body that carries the hymenial layer is called the hymenophore . In lower forms, it remains smooth, while in more highly organized forms it forms plates, tubes or spikes.
Smooth gimenofor at Clavulina cristata
Spiky hymenophore in Hydnum repandum
Tubular hymenophore in Polyporus varius
Lamellar hymenophore in Lactarius chrysorrheus
Representatives
According to modern ideas, the Basidiomycota division is divided into three subdivisions and one class not included in the subdivision. According to the 2008 assumption, there are 16 classes, 52 orders , 177 families , 1589 genera, and 31515 species of basid mushrooms in the world [4] .
Traditionally, the department was divided into two classes - Homobasidiomycetes RT Moore , 1971 (including hat-cuticles and other fungi) and Heterobasidiomycetes RT Moore, 1980 (jelly-like, rust -like mushrooms, as well as oystomycetes ). Previously, the department of basidiomycetes was considered in the rank of the class Basidiomycetes Whittaker , 1959 .
Agaricomycotina Branch
It includes the former classes of Hymenomycetes ( Hymenomycetes Fr. , 1821 ) and Gasteromycetes ( Gasteromycetes Fr. , 1821 ), as well as most jelly-like mushrooms [5] .
Classes :
- Agaricomycetes Doweld, 2001 - Agaricomycetes
- Dacrymycetes Doweld, 2001 - Dacrimycetes
- Tremellomycetes Doweld, 2001 - Tremellomycetes
Pucciniomycotina Branch
The main differentiating features: simple septal pores, the absence of parentosomes, the presence of mannans in the cell wall.
It includes rust fungi, a number of fungi previously classified as smut fungi , as well as a group of other species that are often parasitic on plants [6] .
Classes:
- Agaricostilbomycetes Bauer et al. , 2006 [1] - Agaricostylbomycetes
- Atractiellomycetes Bauer et al. , 2006 [1] - Attractiellomycetes
- Classiculomycetes Bauer et al. , 2006 [1] - Classicomycetes
- Cryptomycocolacomycetes Bauer et al. , 2006 [1] - Cryptomycolocolomycetes
- Cystobasidiomycetes Bauer et al. , 2006 [1] - Cystobazidiomycetes
- Microbotryomycetes Bauer et al. , 2006 [1] - Microbotriomycetes
- Mixiomycetes Bauer et al. , 2006 [1] - Mixomyomycetes
- Pucciniomycetes Bauer et al. , 2006 [1] - Pucciniomycetes
- Tritirachiomycetes Aime & Schell, 2011 - Tritirachiomycetes
Ustilaginomycotina Branch
The main differentiating features: non-perforated, simple or with a roll-like thickening of the perforated area, septal pores with a membrane cap in most species, hemispherical polar bodies of the spindle of division, lack of mannans in the cell membrane.
Includes most smut fungi, as well as Exobasidiales [7] .
Classes:
- Exobasidiomycetes Begerow, M. Stoll & R. Bauer, 2006 - Exobazidiomycetes
- Entorrhizomycetes Begerow, M. Stoll & R. Bauer, 2006 - Entorrhizomycetes
- Malasseziomycetes Denchev & T. Denchev, 2014 - Malassesiomycetes [8] [9]
- Monilielliomycetes QM Wang, FY Bai & Boekhout, 2014 - Moniliellomycetes [9]
- Ustilaginomycetes R. Bauer, Oberw. & Vánky , 1997 - Ostomycetes
incertae sedis
Grade:
- Wallemiomycetes Zalar , de Hoog & Schroers , 2005 - Wallemiomycetes
Environmental Functions
Basidiomycetes, mainly saprotrophs , play an important role in the mineralization of organic compounds, especially intractable ones ( cellulose , lignin ). Mushrooms secrete their enzymes into the medium and absorb the entire organic matter decay products, destroying much more substances than they actually use. Basidiomycetes are most widespread in forest soils and litter.
Many basidiomycetes act as symbionts of plants (see mycorrhiza , lichens ), while others act as plant parasites ( mushrooms , tinder fungus , smut , rust mushrooms ).
Notes
- ↑ 1 2 3 4 5 6 7 8 9 10 Bauer R., Begerow D., Sampaio JP, Weiβ M., Oberwinkler F. The simple-septate basidiomycetes: a synopsis // Mycological Progress. - 2006. - Vol. 5, No. 1 . - P. 41-66. - DOI : 10.1007 / s11557-006-0502-0 .
- ↑ Belyakova G.A., Dyakov Yu.T., Tarasov K.L. Botanika: 4 t. - M .: Academy, 2006. - T. 2. - 320 s. - ISBN 978-5-7695-2750-1 .
- ↑ Garibova L.V., Lekomtseva S.N. Fundamentals of mycology. - M. , 2005. - ISBN 5-87317-265-X .
- ↑ Kirk et al ., Pp. 78-79.
- ↑ Kirk et al ., P. 13.
- ↑ Kirk et al ., P. 581.
- ↑ Kirk et al ., P. 717-718.
- ↑ Denchev CM, Denchev TT Nomenclatural novelties // Index Fungorum. - 2014. - No. 145 .
- ↑ 1 2 Wang Q.-M., Theelen B., Groenewald, M., Bai F.-Y., Boekhout T. Moniliellomycetes and Malasseziomycetes, two new classes in Ustilaginomycotina // Persoonia. - 2014 .-- Vol. 33. - P. 41–47. - DOI : 10.3767 / 003158514X682313 .
Literature
- Kirk PM, Cannon PF, Minter DW, Stalpers JA Ainsworth and Bisby's Dictionary of the Fungi. - 10th editon. - CAB International. - ISBN 978 0 85199 826 8 .