Teleomorph, anamorph and holomorph

Source: Wikipedia, the free encyclopedia.
This article is about life cycles of fungi. For other uses, see Anamorph (disambiguation).

In

fungi in the phyla Ascomycota and Basidiomycota
:

  • Teleomorph: the sexual reproductive stage (morph), typically a fruiting body. (The sexual state of a fungus.)
  • Anamorph: an asexual reproductive stage (morph), often
    mold
    -like. When a single fungus produces multiple morphologically distinct anamorphs, these are called synanamorphs.
  • Holomorph: the whole fungus, including anamorphs and teleomorph. (Homothallic = A fungus capable of sexual reproduction on a single thallus{body})

Dual naming of fungi

Fungi are classified primarily based on the structures associated with sexual reproduction, which tend to be evolutionarily conserved. However, many fungi reproduce only asexually, and cannot easily be classified based on sexual characteristics; some produce both asexual and sexual states. These species are often members of the Ascomycota, but a few of them belong to the Basidiomycota. Even among fungi that reproduce both sexually and asexually, often only one method of reproduction can be observed at a specific point in time or under specific conditions. Additionally, fungi typically grow in mixed colonies and sporulate amongst each other. These facts have made it very difficult to link the various states of the same fungus.

Fungi that are not known to produce a teleomorph were historically placed into an artificial

molecular phylogeny allows accurate placement of species which are known from only part of their life cycle. Others retain the term "deuteromycetes," but give it a lowercase "d" and no taxonomic rank.[1]

Historically, Article 59 of the

International Code of Botanical Nomenclature permitted mycologists to give asexually reproducing fungi (anamorphs) separate names from their sexual states (teleomorphs);[2] but this practice was discontinued as of 1 January 2013.[3]

The dual naming system can be confusing.[4] However, it is essential for workers in plant pathology, mold identification, medical mycology, and food microbiology, fields in which asexually reproducing fungi are commonly encountered.[clarification needed]

From dual system to single nomenclature

The separate names for anamorphs of fungi with a pleomorphic life-cycle has been an issue of debate since the phenomenon was recognized in the mid-19th century.

mycologists – even ones working on the same genus.[3] Following intensive discussions under the auspices of the International Mycological Association, drastic changes were made at the International Botanical Congress in 1981 to clarify and simplify the procedures – and the new terms anamorph, teleomorph, and holomorph entered general use.[3] An unfortunate effect of the simplification was that many name changes had to be made, including for some well-known and economically important species; at that date, the conservation of species names was not allowed under the Code.[3]

Unforeseen in the 1970s, when the 1981 provisions were crafted, was the impact of

epitypified by material showing the sexual stage when it was discovered, and for that anamorph name to continue to be used.[3]

The 1995 edition of the influential Ainsworth and Bisby’s Dictionary of the Fungi sought to replace the term anamorph with mitosporic fungus and teleomorph with meiosporic fungus, based on the idea that the fundamental distinction is whether mitosis or meiosis preceded sporulation. This is a controversial choice because it is not clear that the morphological differences which traditionally define anamorphs and teleomorphs line up completely with sexual practices, or whether those sexual practices are sufficiently well understood in some cases.[1]

The Vienna Congress (2005) established a Special Committee to investigate the issue further, but it was unable to reach a consensus.

molecular phylogenetic approaches started to ignore the provisions, or interpret them in different ways.[3]

One fungus, one name

The International Botanical Congress in Melbourne in July 2011 made a change in the International Code of Nomenclature for algae, fungi, and plants and adopted the principle "one fungus, one name".[3] After 1 January 2013, one fungus can only have one name; the system of permitting separate names to be used for anamorphs then ended.[3] This means that all legitimate names proposed for a species, regardless of what stage they are typified by, can serve as the correct name for that species.[3][6]

All names now compete on an equal footing for

lichenicolous fungi) had always been excluded from the provisions permitting dual nomenclature.[3]

The problem of choosing one name among many remains to be examined for many large, agriculturally or medically-important genera like Aspergillus and Fusarium. Articles have been published on such specific genera to propose ways to define them under the newer rules.[7][8]

See also

References

This article incorporates CC-BY-3.0 text from the reference[3]

  1. ^
    PMID 10398676
  2. International Code of Botanical Nomenclature
  3. ^
    doi:10.3897/mycokeys.1.2062
    .
  4. U.S. CDC
    . July 9, 2021. Retrieved October 1, 2023.
  5. ^ Cannon, P. F.; Kirk, P. M. (2000). "The philosophies and practicalities of amalgamating anamorph and teleomorph concepts". Studies in Mycology. 45: 19–25.
  6. ISBN 978-3-87429-425-6
  7. doi:10.12705/653.10
    .
  8. PMID 23379853
    .

9. https://www.adelaide.edu.au/mycology/glossary

External links

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