''Olpidium'' is a

fungal 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 th ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

in the family

Olpidiaceae Olpidiaceae is a fungal plant pathogen family of genera, that was placed in the order Olpidiales. Taxonomy Based on the work of Philippe Silar and "The Mycota: A Comprehensive Treatise on Fungi as Experimental Systems for Basic and Applied Resear ...

. Members of ''Olpidium'' are

zoosporic A zoospore is a motile asexual spore that uses a flagellum for locomotion. Also called a swarm spore, these spores are created by some protists, bacteria, and fungi to propagate themselves. Diversity Flagella types Zoospores may possess one or m ...

pathogen In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ ...

s of

plant Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclud ...

animal Animals are multicellular, eukaryotic organisms in the Kingdom (biology), biological kingdom Animalia. With few exceptions, animals Heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, are Motilit ...

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 ...

, and

oomycete Oomycota forms a distinct phylogenetic lineage of fungus-like eukaryotic microorganisms, called oomycetes (). They are filamentous and heterotrophic, and can reproduce both sexually and asexually. Sexual reproduction of an oospore is the resul ...

Morphology

''Olpidium'' species exist as spherical zoosporangia inside the cells of their host. Zoospores emerge from a single discharge tube and have a single, posterior whiplash

flagellum A flagellum (; ) is a hairlike appendage that protrudes from certain plant and animal sperm cells, and from a wide range of microorganisms to provide motility. Many protists with flagella are termed as flagellates. A microorganism may have f ...

. Resting spores can be smooth or ornamented.

Ecology

''Olpidium'' species infect a wide variety of plants, animals, protists, and fungi and are fairly common in aquatic and terrestrial ecosystems. Most of what is known about the genus comes from those species that infect higher plants, especially crops. In higher plants, infection with ''Olpidium'' often causes little to no symptoms. An exception is ''

Olpidium viciae ''Olpidium'' is a fungal genus in the family Olpidiaceae. Members of ''Olpidium'' are zoosporic pathogens of plants, animals, fungi, and oomycetes. Morphology ''Olpidium'' species exist as spherical zoosporangia inside the cells of their host ...

'', which causes

broadbean ''Vicia faba'', commonly known as the broad bean, fava bean, or faba bean, is a species of vetch, a flowering plant in the pea and bean family Fabaceae. It is widely cultivated as a crop for human consumption, and also as a cover crop. Var ...

blister. However, ''Olpidium'' species can vector

plant virus Plant viruses are viruses that affect plants. Like all other viruses, plant viruses are obligate intracellular parasites that do not have the molecular machinery to replicate without a host. Plant viruses can be pathogenic to higher plants. M ...

es. For example, ''

Olpidium brassicae ''Olpidium brassicae'' is a plant pathogen, it is a fungal obligate parasite. In 1983, the Alsike, Alberta area's clover (which is a major part of horses' diet) was struck by a fungus epidemic of ''Olpidium brassicae'', previously not seen in Ca ...

'' transmits big-vein virus and big-vein associated varicosavirus among lettuce plants, and transmits

tobacco mosaic virus ''Tobacco mosaic virus'' (TMV) is a positive-sense single-stranded RNA virus species in the genus ''Tobamovirus'' that infects a wide range of plants, especially tobacco and other members of the family Solanaceae. The infection causes characteri ...

among tobacco plants. ''

Olpidium bornovanus ''Olpidium'' is a fungal genus in the family Olpidiaceae. Members of ''Olpidium'' are zoosporic pathogens of plants, animals, fungi, and oomycetes. Morphology ''Olpidium'' species exist as spherical zoosporangia inside the cells of their host ...

'' or ''

Olpidium cucurbitacearum ''Olpidium'' is a fungal genus in the family Olpidiaceae. Members of ''Olpidium'' are zoosporic pathogens of plants, animals, fungi, and oomycetes. Morphology ''Olpidium'' species exist as spherical zoosporangia inside the cells of their host ...

'' serves as a vectors for a number of curcubit viruses.

Taxonomy

The genus ''Olpidium'' was placed in the

in the

Chytridiales Fungi of the order Chytridiales, like other members of its division Division or divider may refer to: Mathematics *Division (mathematics), the inverse of multiplication *Division algorithm, a method for computing the result of mathematical di ...

. Later some species, notably ''O. brassicae'', were moved to the genus '' Pleotrachelus'', but these were later moved back into the genus. Based on zoospore ultrastructure, Donald J. S. Barr moved the genus into

Spizellomycetales Spizellomycetales is an Order (biology), order of fungi in the Chytridiomycetes. Spizellomycetalean chytrids are essentially ubiquitous zoospore-producing fungi found in soils where they decompose pollen. Recently they have also been found in dun ...

In studies using molecular

phylogenetics In biology, phylogenetics (; from Greek language, Greek wikt:φυλή, φυλή/wikt:φῦλον, φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary his ...

, ''O. brassicae'', ''Olpidium virulentus, O. virulentus'', and ''O. bornovanus'' were found to cluster with members of the former

Zygomycota Zygomycota, or zygote fungi, is a former division or phylum of the kingdom Fungi. The members are now part of two phyla: the Mucoromycota and Zoopagomycota. Approximately 1060 species are known. They are mostly terrestrial in habitat, living i ...

not with members of

Chytridiomycota Chytridiomycota are a division of zoosporic organisms in the kingdom Fungi, informally known as chytrids. The name is derived from the Ancient Greek ('), meaning "little pot", describing the structure containing unreleased zoöspores. Chytrids ...

. One researcher, has elevated ''Olpidium'' to the level of phylum (

Olpidiomycota Olpidiaceae is a fungal plant pathogen family of genera, that was placed in the order Olpidiales. Taxonomy Based on the work of Philippe Silar and "The Mycota: A Comprehensive Treatise on Fungi as Experimental Systems for Basic and Applied Resear ...

) and split the genus into several genera. While nomenclaturaly valid and accepted by some researchers, others view these changes as controversial and unsupported.

References

External links

Index Fungorum
Chytridiomycota genera {{Chytridiomycota-stub