Smut fungus

Smut fungus
Corn blight ( Ustilago maydis )
Systematics
Empire : Mushrooms (fungi) Sub-kingdom : Dikarya Department : Stand mushrooms (Basidiomycota) Subdivision : Ustilaginomycotina Class : Ustilaginomycetes Order : Smut fungus
Scientific name
Ustilaginales
( G. Winter ) Bauer & Oberwinkler

The smut fungi (Ustilaginales) are by far the most species-rich group of smut fungi (Ustilaginomycotina). The most species-rich genera are Ustilago and Sporisorium . All representatives are parasites on flowering plants .

Features and ecology

The smut fungi usually form their spores in the flowers ( ovaries or anthers ) of their hosts. Fruit bodies are not formed. They have dark-colored, thick-walled teliospores and germinate with mostly four-cell phragmobasidia .

They parasitize on higher plants and grow intercellularly.

Life cycle

The basidiospores are bipolarly determined (+ and -). They germinate into a haploid , yeast-like mycelium that lives exclusively in saprobionic form , it cannot parasitize on plants. When two differently determined cells meet, a copulation tube forms. Through this, the contents of one cell migrate over to the other: the cells fuse (plasmogamy), the two nuclei are preserved. A pair of nuclei (dikaryotic) cell develops. From this a pair-seeded hypha grows , which can now attack a host plant.

The paired mycelium spreads intercellularly in the host plant. It grows with the apical meristem and does not cause any symptoms. In species-specific organs, such as the anthers or in the ovary , the mycelium changes to intracellular growth, destroying the host tissue and forming dense mycelium layers. In these, spherical swellings arise, which receive thick brown-black cell walls and detach from the mycelium: the burn spores, so-called after their coal-dust-like appearance. The smut spores are homologous to young basidia , in them karyogamy takes place . They are called probasidia. In most species, the burn spores overwinter and germinate in spring, forming a transversely septate hyphae tube. This is where meiosis takes place. At the end of meiosis there are four cells, each with a haploid nucleus. This stage, known as Promyzel, corresponds to a phragmobasidy . Spores are pinched off laterally from this (sporidia), this can happen several times in a row. This concludes the haplo-dikaryotic cycle.

meaning

The smut fungi are economically important pests on arable crops, especially on cereals. Examples are corn smut ( Ustilago maydis ), the oat smut ( Ustilago avenae ), barley loose smut ( Ustilago hordei ) and wheat loose smut ( Ustilago tritici ).

Systematics

As a monophyletic group, the smut fungus form one of the two orders of the Ustilaginomycetes .

In the last few years the species-rich family of the smut fungus relatives (Ustilaginaceae) has been divided into several smaller families, the regrouping has not yet been completed. Begerow et al. (2006) subdivide the fungus-like species as follows:

• Anthracoideaceae : hosts are Cyperaceae and Juncaceae .
  • Anthracoidea
  • Cintractia
  • Dermatosorus
  • Farysia
  • Heterotolyposporium
  • Moreaua
  • Planetella
  • Schizonella
  • Stegocintractia
  • Tolyposporium
  • Trichocintractia
  • The following genera are provisionally placed in the family Anthracoideaceae:
  • Cintractiella
  • Farysporium
  • Gymnocintractia
  • Kuntzeomyces
  • Leucocintractia
  • Orphanomyces
  • Pilocintractia
  • Testicularia
  • Ustanciosporium
• Melanotaeniaceae
  • Exoteliospora
  • Melanotaenium
  • Yelsemia
• Fire fungus relatives (Ustilaginaceae): hosts are Poaceae (except for Melanopsichium )
  • Melanopsichium
  • Moesziomyces
  • Pseudozyma ( anamorphic )
  • Sporisorium
  • Ustilago
  • The following genera are provisionally placed in the family Ustilaginaceae:
  • Franzpetrakia
  • Macalpinomyces
  • Tranzscheliella
• Websdaneaceae : hosts are Restionaceae
  • Restiosporium
  • Websdanea
• incertae sedis (not assigned to any family)
  • Clintamra
  • Eriocaulago
  • Eriomoeszia
  • Eriosporium
  • Geminago
  • Pericladium
  • Uleiella

swell

literature

• Dominik Begerow, Matthias Stoll, Robert Bauer: A phylogenetic hypothesis of Ustilaginomycotina based on multiple gene analyzes and morphological data . In: Mycologia . tape 98 , no. 6 , 2006, p. 906-916 , doi : 10.3852 / mycologia.98.6.906 ( PDF; 2.54 MB ).

• Andreas Bresinsky, Christian Körner, Joachim W. Kadereit, G. Neuhaus: Strasburger - textbook of botany . 36th edition. Spektrum Akademischer Verlag, Heidelberg 2008, ISBN 978-3-8274-1455-7 , p. 672 f .

Individual evidence

1. ↑ David S. Hibbett, Manfred Binder, Joseph F. Bischoff, Meredith Blackwell, Paul F. Cannon, Ove E. Eriksson, Sabine Huhndorf, Timothy James, Paul M. Kirk, Robert Lücking, H.; Thorsten Lumbsch, François Lutzoni, P. Brandon Matheny, David J. McLaughlin, Martha J. Powell, Scott Redhead, Conrad L. Schoch, Joseph W. Spatafora, Joost A. Stalpers, Rytas Vilgalys, M. Catherine Aime, André Aptroot, Robert Bauer, Dominik Begerow, Gerald L. Benny, Lisa A. Castlebury, Pedro W. Crous, Yu-Cheng Dai, Walter Gams, David M. Geiser, Gareth W. Griffith, Cécile Gueidan, David L. Hawksworth, Geir Hestmark, Kentaro Hosaka, Richard A. Humber, Kevin D. Hyde, Joseph E. Ironside, Urmas Kõljalg, Cletus P. Kurtzman, Karl-Henrik Larsson, Robert Lichtwardt, Joyce Longcore, Jolanta Miądlikowsk, Andrew Miller, Jean-Marc Moncalvo, Sharon Mozley-Standridge, Franz Oberwinkler, Erast Parmasto, Valérie Reeb, Jack D. Rogers, Claude Roux, Leif Ryvarden, José Paulo Sampaio, Arthur Schüßler, Junta Sugiyama, R. Greg Thorn, Lei f Tibell, Wendy A. Untereiner, Christopher Walker, Zheng Wang, Alex Weir, Michael Weiss, Merlin M. White, Katarina Wink, Yi-Jian Yao, Ning Zhang: A higher-level phylogenetic classification of the Fungi . In: Mycological Research . tape 111 (5) . British Mycological Society, 2007, p. 509-547 , doi : 10.1016 / j.mycres.2007.03.004 ( PDF; 1.01 MB ).

Web links

Commons : Ustilaginales  - Collection of images, videos, and audio files