The Pucciniomycetes (formerly known as the Urediniomycetes) are a class of

fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...

in the

Pucciniomycotina Pucciniomycotina is a subdivision of fungus within the division Basidiomycota. The subdivision contains 9 classes, 20 orders, and 37 families. Over 8400 species of Pucciniomycotina have been described - more than 8% of all described fungi. Th ...

subdivision of the Basidiomycota. The class contains 5 orders, 21

families Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Ideal ...

, 190 genera, and 8016

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

. It includes several important plant pathogens causing forms of fungal

rust Rust is an iron oxide, a usually reddish-brown oxide formed by the reaction of iron and oxygen in the catalytic presence of water or air moisture. Rust consists of hydrous iron(III) oxides (Fe2O3·nH2O) and iron(III) oxide-hydroxide (FeO( ...

Characteristics

Pucciniomycetes develop no

basidiocarp In fungi, a basidiocarp, basidiome, or basidioma () is the sporocarp of a basidiomycete, the multicellular structure on which the spore-producing hymenium is borne. Basidiocarps are characteristic of the hymenomycetes; rusts and smuts do ...

karyogamy Karyogamy is the final step in the process of fusing together two haploid eukaryotic cells, and refers specifically to the fusion of the two nuclei. Before karyogamy, each haploid cell has one complete copy of the organism's genome. In order for ...

occurs in a thick-walled resting spore (

teliospore Teliospore (sometimes called teleutospore) is the thick-walled resting spore of some fungi ( rusts and smuts), from which the basidium arises. Development They develop in '' telia'' (sing. ''telium'' or ''teliosorus''). The telial host is the p ...

), and

meiosis Meiosis (; , since it is a reductional division) is a special type of cell division of germ cells in sexually-reproducing organisms that produces the gametes, such as sperm or egg cells. It involves two rounds of division that ultimately r ...

occurs upon germination of teliospore. They have simple

septal pore In algal anatomy, a pit connection is a hole in the septum between two algal cells, and is found only in the red algae − specifically, all orders except the Porphyridiales and haploid Bangiales. They are often stoppered with proteinaceous "pit ...

s without membrane caps and disc-like spindle pole bodies. Except for a few species, the

basidia A basidium () is a microscopic sporangium (a spore-producing structure) found on the hymenophore of fruiting bodies of basidiomycete fungi which are also called tertiary mycelium, developed from secondary mycelium. Tertiary mycelium is highly- ...

, when present, are transversally septate.

Mannose Mannose is a sugar monomer of the aldohexose series of carbohydrates. It is a C-2 epimer of glucose. Mannose is important in human metabolism, especially in the glycosylation of certain proteins. Several congenital disorders of glycosylation ...

is the major cell wall carbohydrate,

glucose Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, u ...

fucose Fucose is a hexose deoxy sugar with the chemical formula C6H12O5. It is found on ''N''-linked glycans on the mammalian, insect and plant cell surface. Fucose is the fundamental sub-unit of the seaweed polysaccharide fucoidan. The α(1→3) li ...

and rhamnose are the less prevalent neutral sugars and

xylose Xylose ( grc, ξύλον, , "wood") is a sugar first isolated from wood, and named for it. Xylose is classified as a monosaccharide of the aldopentose type, which means that it contains five carbon atoms and includes an aldehyde functional g ...

is not present.

References

Basidiomycota classes Pucciniomycotina {{Basidiomycetes-stub