Urediniomycetes is a diverse class of fungi that includes several important plant pathogens causing forms of fungal rust. It is the only class in the subdivision Teliomycotina of basidiomycetes .

Characteristics

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Urediniomycetes develop no basidiocarp, karyogamy occurs in a thick-walled resting spore (teliospore), and meiosis occurs upon germination of teliospore. They have simple septal pores without membrane caps and disc-like spindle pole bodies. Except for a few species, the basidia are transversally septate. Mannose is the major cell wall carbohydrate, glucose, fucose and rhamnose are the less prevalent neutral sugars and xylose is not present.

Systematics

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The class contains approximately 7400 species, distributed among approximately 215 genera, but can be much larger as many cryptic species are recognized. More than 95% of the species and 75% of the genera are placed in the order Uredinales. Due to the rapid accumulation of new data, the classification of Urediniomycetes is still under development. Currently, the class is divided into the orders Agaricostilbales, Atractiellales, Classiculales, Microbotryales, Septobasidiales, Sporidiales and Uredinales. Three subclasses (Urediniomycetidae, Agaricostilbomycetidae and Microbotryomycetidae) have been proposed. An attempt of integrated consensus-classification is presented below:

• Subclass: Microbotryomycetidae

Order: Cryptomycocolacales Oberwinkler & Bauer

Family: Cryptomycocolacaceae Oberwinkler & Bauer

Order: Heterogastridiales Oberwinkler & Bauer

Family: Heterogastridiaceae Oberwinkler & Bauer

Order: Leucosporidiales Sampaio, Weiss & Bauer

Order: Sporidiobolales Sampaio, Weiss & Bauer

Family: Sporidiobolaceae Moore emend. Sampaio, Weiss & Bauer

Order: Microbotryales Bauer & Oberwinkler

Family: Microbotryaceae Moore

Family: Ustilentylomataceae Bauer & Oberwinkler

Taxa of the Microbotryomycetidae incertae sedis

Family: Krieglsteineraceae Pouzar

Family: Camptobasidiaceae Moore

Genera: Atractocolax, Bensingtonia, Colacogloea, Kriegeria

• Subclass: Agaricostilbomycetidae

Order: Agaricostilbales Oberwinkler & Bauer

Family: Agaricostilbaceae Oberwinkler & Bauer

Family: Chionosphaeraceae Oberwinkler & Bandon

Taxa of the Agaricostilbomycetidae incertae sedis

Genera: Bensingtonia, Kondoa, Kurtzmanomyces, Mycogloea, Sporobolomyces, Sterigmatomyces, Spiculogloea, Zygogloea

• Subclass: Urediniomycetidae

Order: Uredinales Arthur

14 families

Order: Septobasidiales Couch ex Donk

Family: Septobasidiaceae Maire

Family: Pachnocybaceae Oberwinkler & Bauer

Order: Platygloeales Moore

Taxa of the Urediniomycetidae incertae sedis

Family: Eocronartiaceae Jülich

Genera: Helicobasidium, Herpobasidium, Insolibasidium, Jola, Platycarpa, Ptechetelium

• Other groups of uncertain position:

Order Atractiellales Oberwinkler & Bandoni

Family: Hoehnelomycetaceae Jülich

Family: Phleogenaceae Weese

Family: Helicogloeaceae Jülich

Order: Classiculales Bauer, Begerow, Oberwinkler & Marvanová

Family: Classiculaceae Bauer, Begerow, Oberwinkler & Marvanová

Order: Cystobasidiales (Bauer & Sampaio, in prep.)

References

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• The Tree of Life page on Urediniomycotina^*
• The Classification of Dimorphic Basidiomycetes^*

Basidiomycetes