| Xylonomycetes | |
|---|---|
 | |
| Four-week old culture of Xylona heveae growing on Potato dextrose agar | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Xylonomycetes Gazis & P. Chaverri, 2012 [1] |
| Orders | |
The Xylonomycetes are a class of fungi, [2] which holds 2 orders of SymbiotaphrinalesBaral & E. Weber, [3] and XylonalesGazis & P. Chaverri. [4] [5]
During a culture-based survey of living sapwood and leaves of rubber trees ( Hevea spp.) in remote forests of Peru. Multilocus phylogenetic analyses reveal that this new lineage came from the radiation of the Leotiomyceta class which generated several other classes including Arthoniomycetes, Dothideomycetes, Eurotiomycetes, Geoglossomycetes, Lecanoromycetes, Leotiomycetes, Lichinomycetes and Sordariomycetes. Due to the unique morphological, physiological, and ecological traits relative to known endophytes, Xylonomycetes was deemed unique enough to be separate. [1]
Within the superclass of Pezizomycotina, the 6 classes (including Pezizomycetes and Orbiliomycetes) were monophyletic apart from Xylonomycetes. Xylonomycetes, Eurotiomycetes and Dothideomycetes were deemed to have had a single origin. [6]
They contain unspecific peroxygenases (UPO) enzymes which can be used to determine taxonomic afflication. [7]
It contains the wood endophytes in Xylona and the endosymbionts of beetles in Symbiotaphrina. [8] It has been suggested that these seeming unrelated genera might be linked via a yeast-like stage. As an asexual yeast living within the insect guts, with an asexual mycelial form and then a sexual form associated with the dead wood. Although, the frequency of transfer between free-living and symbiotic conditions is unknown and could be very low. As the yeasts are transferred vertically via the ovipositor of the female inset to the egg surface. [9]
Xylonomycetes holds (orders and families);
Ascomycota is a phylum of the kingdom Fungi that, together with the Basidiomycota, forms the subkingdom Dikarya. Its members are commonly known as the sac fungi or ascomycetes. It is the largest phylum of Fungi, with over 64,000 species. The defining feature of this fungal group is the "ascus", a microscopic sexual structure in which nonmotile spores, called ascospores, are formed. However, some species of Ascomycota are asexual and thus do not form asci or ascospores. Familiar examples of sac fungi include morels, truffles, brewers' and bakers' yeast, dead man's fingers, and cup fungi. The fungal symbionts in the majority of lichens such as Cladonia belong to the Ascomycota.
Ambrosia beetles are beetles of the weevil subfamilies Scolytinae and Platypodinae, which live in nutritional symbiosis with ambrosia fungi. The beetles excavate tunnels in dead or stressed trees into which they introduce fungal gardens, their sole source of nutrition. After landing on a suitable tree, an ambrosia beetle excavates a tunnel in which it releases its fungal symbiont. The fungus penetrates the plant's xylem tissue, extracts nutrients from it, and concentrates the nutrients on and near the surface of the beetle gallery. Ambrosia fungi are typically poor wood degraders, and instead utilize less demanding nutrients. Symbiotic fungi produce and detoxify ethanol, which is an attractant for ambrosia beetles and likely prevents growth of antagonistic pathogens and selects for other beneficial symbionts. The majority of ambrosia beetles colonize xylem of recently dead trees, but some colonize stressed trees that are still alive, and a few species attack healthy trees. Species differ in their preference for different parts of trees, different stages of deterioration, and in the shape of their tunnels ("galleries"). However, the majority of ambrosia beetles are not specialized to any taxonomic group of hosts, unlike most phytophagous organisms including the closely related bark beetles. One species of ambrosia beetle, Austroplatypus incompertus exhibits eusociality, one of the few organisms outside of Hymenoptera and Isoptera to do so.
Pezizomycotina make up most of the Ascomycota fungi and include most lichenized fungi too. Pezizomycotina contains the filamentous ascomycetes and is a subdivision of the Ascomycota'. It is more or less synonymous with the older taxon Euascomycota. These fungi reproduce by fission rather than budding and this subdivision includes almost all the ascus fungi that have fruiting bodies visible to the naked eye.
Eurotiomycetes is a large class of ascomycetes with cleistothecial ascocarps within the subphylum Pezizomycotina, currently containing around 3810 species according to the Catalogue of Life. It is the third largest lichenized class, with more than 1200 lichen species that are mostly bitunicate in the formation of asci. It contains most of the fungi previously known morphologically as "Plectomycetes".
Saccharomycotina is a subdivision (subphylum) of the division (phylum) Ascomycota in the kingdom Fungi. It comprises most of the ascomycete yeasts. The members of Saccharomycotina reproduce by budding and they do not produce ascocarps.
Dothideomycetes is the largest and most diverse class of ascomycete fungi. It comprises 11 orders 90 families, 1,300 genera and over 19,000 known species. Wijayawardene et al. in 2020 added more orders to the class.
The Clavicipitaceae are a family of fungi within the order Hypocreales. A 2008 estimate placed 43 genera in the family, but a study in 2020 has increased this number to 50.
The Xylariales are an order of fungi within the class Sordariomycetes, subdivision Pezizomycotina, division Ascomycota. It was the original order of the subclass Xylariomycetidae. Xylariales was circumscribed in 1932 by Swedish mycologist John Axel Nannfeldt, and Xylariomycetidae by Ove Erik Eriksson and Katarina Winka in 1997. In 2020, more families were added to the order.
Epichloë is a genus of ascomycete fungi forming an endophytic symbiosis with grasses. Grass choke disease is a symptom in grasses induced by some Epichloë species, which form spore-bearing mats (stromata) on tillers and suppress the development of their host plant's inflorescence. For most of their life cycle however, Epichloë grow in the intercellular space of stems, leaves, inflorescences, and seeds of the grass plant without incurring symptoms of disease. In fact, they provide several benefits to their host, including the production of different herbivore-deterring alkaloids, increased stress resistance, and growth promotion.
Pleosporaceae is a family of sac fungi. They are pathogenic to humans or saprobic on woody and dead herbaceous stems or leaves.
The Botryosphaeriales are an order of sac fungi (Ascomycetes), placed under class Dothideomycetes. Some species are parasites, causing leaf spot, plant rot, die-back or cankers, but they can also be saprophytes or endophytes. They occur world-wide on many hosts. For example, in China, infections related to Botryosphaeriales have been recorded on numerous hosts such as grapes, Caragana arborescens,Cercis chinensis, Eucalyptus, Chinese hackberry, blueberry, forest trees, and various other woody hosts.
Arthoniomycetes are a class of ascomycete fungi. It includes two orders: Arthoniales and Lichenostigmatales. Most of the taxa in these orders are tropical and subtropical lichens.
The Acarosporales are an order of fungi in the class Lecanoromycetes. Phylogenetic analyses conducted using the sequences of both the protein-coding gene RPB2 as well as nuclear ribosomal genes place this order within the subclass Acarosporomycetidae.
Lichinales is the sole order of ascomycete fungi in the class Lichinomycetes. It contains three families: Gloeoheppiaceae, Lichinaceae, and Peltulaceae. Most species are lichenized. Lichinales was proposed in 1986 by German lichenologists Aino Henssen and Burkhard Büdel. The class Lichinomycetes was created by Valérie Reeb, François Lutzoni and Claude Roux in 2004.
Lophiostoma is a genus of ascomycetous fungi in the family Lophiostomataceae.
Symbiotaphrina is a genus including seven species of fungi in the monotypic family Symbiotaphrinaceae Baral & E. Weber and the monotypic order Symbiotaphrinales Baral & E. Weber.
Black yeasts, sometimes also black fungi, dematiaceous fungi, microcolonial fungi or meristematic fungi is a diverse group of slow-growing microfungi which reproduce mostly asexually. Only few genera reproduce by budding cells, while in others hyphal or meristematic (isodiametric) reproduction is preponderant. Black yeasts share some distinctive characteristics, in particular a dark colouration (melanisation) of their cell wall. Morphological plasticity, incrustation of the cell wall with melanins and presence of other protective substances like carotenoids and mycosporines represent passive physiological adaptations which enable black fungi to be highly resistant against environmental stresses. The term "polyextremotolerance" has been introduced to describe this phenotype, an example of which is the species Aureobasidium pullulans. Presence of 1,8-dihydroxynaphthalene melanin in the cell wall confers to the microfungi their characteristic olivaceous to dark brown/black colour.
Fungal genomes are among the smallest genomes of eukaryotes. The sizes of fungal genomes range from less than 10 Mbp to hundreds of Mbp. The average genome size is approximately 37 Mbp in Ascomycota, 47 Mbp in Basidiomycota and 75 Mbp in Oomycota. The sizes and gene numbers of the smallest genomes of free-living fungi such as those of Wallemia ichthyophaga, Wallemia mellicola or Malassezia restricta are comparable to bacterial genomes. The genome of the extensively researched yeast Saccharomyces cerevisiae contains approximately 12 Mbp and was the first completely sequenced eukaryotic genome. Due to their compact size fungal genomes can be sequenced with less resources than most other eukaryotic genomes and are thus important models for research. Some fungi exist as stable haploid, diploid, or polyploid cells, others change ploidy in response to environmental conditions and aneuploidy is also observed in novel environments or during periods of stress.
Pisorisporiales is an order of fungi within the phylum of Ascomycota and in the class Sordariomycetes and subdivision of Pezizomycotina and also its own subclass Pisorisporiomycetidae.
Coniothyriaceae is a family of ascomycetous marine based fungi within the order of Pleosporales in the subclass Pleosporomycetidae and within the class Dothideomycetes. They are pathogenic or they can be saprobic on dead branches. They are generally a anamorphic species.