Exobasidiales
Effects of Pflanzenparsiten Exobasidium vaccinii
The Nacktbasidienartigen ( Exobasidiales ) are a group of smut fungi ( Ustilaginomycotina ) and how all the smut fungi, plant parasites.
Characteristics and lifestyle
The system is characterized by a complex interaction apparatus, which makes contact to the host cells via tubes. The representatives form Holobasidien and are dimorphisch, so alternately form saprobiontisch Hefestadien living and parasitic living mycelia. They do not form teliospores and no Ballistokonidien.
The hosts are monocots and dicots, the European representatives infested mainly Ericaceae. They are not real fruit body, the spores occur mainly on the leaves of the host. You solve in the host from the formation of gall -like growths of the mesophyll. The mycelium grows within and / or outside the host cells.
The fungal hyphae penetrate with haustoria into the host cells. In Graphiola the haustoria are constricted at the entry point to wear a buckle and branch out into several lobes. In most species, the haustoria are schnallenlos and not constricted at Exobasidium they hardly extend into the host cell, while they extend deep in the other genera.
The hyphae penetrate through the stomata to the outside, where they form unseptierte basidia ( Holobasidien ). The sterigmata are blunt and strong spreaded, the basidiospores are curved toward each other. The basidiospores fall from passive. Germination occurs with Quersepten by formation of conidia. In culture, the spores form yeast-like cell clusters during germination.
Interaction apparatus
The interaction apparatus is formed by first accumulating small, primary vesicles at the contact surface to the host cell. They merge into larger secondary vesicles that are ultimately connected by long tubes with each other. The resulting coherent cisterns network is filled with electron- dense material. The network is highly branched and has a number of nodular thickening.
Cell -cell interaction begins with a circular penetration of electron dense material in the fungal cell wall in the direction of host plasma membrane. An electron- dense ring, called interaction ring comes into contact with the plasmalemma of the host. It is followed by a second boost of electron dense material in the zone of the ring. The cistern network fused with the plasma membrane of the fungus and at least partially emptied its contents. The result is a roughly spherical accretion of material onto the host plasmalemma. This material is then enveloped by the host material. In some species, followed by a third transfer of fungal material towards the host. The functional role of these processes is not yet clear.
For species with haustoria are located on each haustorium several interaction devices, of which probably only one, however, is active.
System
The Nacktbasidienartigen among the Exobasidiomycetes. The closest relatives are the Doassansiales with which the Nacktbasidienartigen share the complex interaction apparatus. The monophyly of the Nacktbasidienartigen has been demonstrated in several studies. The order is Begerow et al. (2006 ) can be subdivided as follows:
- Exobasidiaceae Arcticomyces
- Exobasidium
- Laurobasidium
- Muribasidiospora
- Acaromyces ( Anamorphic )
- Botryoconis
- Clinoconidium
- Coniodictyum
- Drepanoconis
- Laurobasidium
- Phacellula
- Brachybasidium
- Dicellomyces
- Exobasidiellum
- Kordyana
- Meira ( Anamorphic )
- Proliferobasidium
- Graphiola
- Stylina
Documents
- Robert Bauer, Franz Winkler top, Kálmán Vánky: Ultra structural markers and systematics in smut fungi and allied taxa. Canadian Journal of Botany, Vol 75, 1997, pp. 1273-1314.
- Dominik Begerow, Matthias Stoll, Robert Bauer: A phylogenetic hypothesis of Ustilaginomycotina based on multiple genetic and morphological data Analyses. Mycologia, Volume 98, 2006, pp. 906-916. doi: 10.3852/mycologia.98.6.906
- A. Bresinsky, Ch grains, JW Kadereit, G. Neuhaus, U. Sonnewald: Strasburger - Textbook of botany. 36th edition, Spektrum Akademischer Verlag, Heidelberg 2008, pp. 673 ISBN 978-3-8274-1455-7