Wallemiomycetes
| Wallemiomycetes | |
|---|---|
| Scientific classification | |
| Kingdom: | |
| Division: | |
| Class: |
Wallemiomycetes
Zalar, de Hoog & Schroers (2005)[1]
|
| Order: |
Wallemiales
Zalar, de Hoog & Schroers (2005)
|
| Family: |
Wallemiaceae
R.T. Moore (1966)[2]
|
| Genus: |
Wallemia
Johan-Olsen (1887)
|
| Type species | |
| Wallemia ichthyophaga |
|
| Species | |
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The Wallemiomycetes are a class of fungi in the division Basidiomycota. It consists of the single order Wallemiales, containing the single family Wallemiaceae, which in turn contains the single genus Wallemia. The phylogenetic origin of the lineage was placed to various parts of Basidiomycota, but according to the analysis of a larger dataset it is a sister group of Agaricomycotina.[3][4] The genus contains species of xerophilic molds that are found worldwide. The three described species (W. sebi, W. muriae, and W. ichthyophaga) are distinguished by size range of conidia (asexual spores), the degree of xerotolerance and ribosomal DNA sequences.[1] They are typically isolated from low-moisture foods (such as cakes, bread, sugar, peanuts, dried fish), indoor air dust, salterns and soil.[1] W. sebi is thought to be one of the causes of the hypersensitivity pneumonitis known as the farmer's lung disease,[5] but since the other two species were recognised and separated from W. sebi only recently, their role in the disease cannot be excluded.[1]
Tolerance to low water activity is generally much more frequent among ascomycetous than basidomycetous fungi, and xerotolerant fungi are also able to grow in regular growth media with normal water activity (unlike, for example, halophilic Archaea).[6] However, species from the genus Wallemia are an exception to both of these rules: all three species can tolerate high concentrations of sugars and salts (W. ichthyophaga grows even in media saturated with sodium chloride), while W. muriae and W. ichthyophaga cannot be cultivated unless the water activity of the medium is lowered.[1]
Cell wall and morphological changes of Wallemia species are thought to play a major role in adaptation to low water activity.[7]
The whole genome sequences of W. sebi[3] and W. ichthyophaga[4] are available.
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 3.0 3.1 Template:Cite pmid/22326418
- ↑ 4.0 4.1 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Template:Cite pmid/19878320
- ↑ Template:Cite pmid/19897760
