''Pithomyces chartarum'' is a fungus predominantly found in subtropical countries and other localities with warmer climates. However, it occurs throughout the world including the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

and

Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherl ...

. ''Pithomyces chartarum'' produces a mycotoxin called sporidesmin when it grows on plants, particularly grasses. Presence of the toxin in

forage Forage is a plant material (mainly plant leaves and stems) eaten by grazing livestock. Historically, the term ''forage'' has meant only plants eaten by the animals directly as pasture, crop residue, or immature cereal crops, but it is also used m ...

grasses causes facial eczema in sheep, and is especially problematic in areas such as New Zealand where sheep are intensively raised. Other health effect of ''P. chartarum'' are not well understood.

History and taxonomy

This species was first discovered by

Miles Berkeley Miles Joseph Berkeley (1 April 1803 – 30 July 1889) was an English cryptogamist and clergyman, and one of the founders of the science of plant pathology. Life Berkeley was born at Biggin Hall, Benefield, Northamptonshire, and educated at R ...

and

Moses Ashley Curtis Moses Ashley Curtis (11 May 1808 – 10 April 1872) was a noted American botanist. Biography Curtis was born in Stockbridge, Massachusetts and educated at Williams College in Massachusetts. After graduating, he became a tutor for the children of ...

as ''Sporidesmium chartarum'' in 1874. It was independently named ''Sporidesmium bakeri'' by German mycologists Hans and

Paul Sydow Paul Sydow (1 November 1851 in Kallies – 26 February 1925 in Sophienstädt near Ruhlsdorf) was a German mycologist and lichenologist, father of Hans Sydow (1879–1946). He worked as a schoolmaster in Berlin. With his son, Hans, he authored w ...

in 1914. Canadian mycologist

Stanley Hughes Stanley Hughes (1918–2019) was a Canadian scientist who is known throughout the global field of mycology for developing and introducing a precise and meticulous system for classifying fungi that is still used today. A naturalized Canadian, he w ...

examined specimens of both taxa in 1958 and concluded that they represented the same taxon which he contemplated assigning them to the genus ''Scheleobrachea''. Several years later, the British mycologist Martin Ellis described the fungus in the genus ''Pithomyces'' as ''P. chartarum''. It has been suggested that ''P. chartarum'' may be indigenous to

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

Growth and morphology

''Pithomyces chartarum'' produces spores that are multicellular and darkly pigmented, although they are produced sparsely. The spores can be barrel-shaped, ellipsoidal or club-shaped. ''Pithomyces chartarum'' has three vegetative hyphal types: sparsely septate, densely septate, and densely septate with surface spines. The colonies are fast growing and their morphology depends on temperature. When the temperature is below , the sparsely septate morphology predominates in contrast to the densely septate for that is stimulated by temperatures of . The spores that are germinating produce hyaline superficial hyphae which can easily penetrate plant cell walls. The conidiophores bear simple conidia, they are short, thin walled and usually nonseptate. The conidia are considered aleurioconidia because they arise singly at the apex of each conidiophore. Conidia may also form in clusters on a network of conidiogenous branches. Mature conidia typically have three transverse septa and up to two longitudinal septa.

Physiology

The production of conidia and vegetative hyphae are good at . Conidia require free water to germinate and do not germinate at water potentials below -140 bars. The production of conidia is stimulated in vitro by exposure to near UV-light. Warm ground temperatures and high humidity cause rapid growth but lower temperatures result in higher sporidesmin content of conidia. ''Pithomyces chartarum'' produces sporidesmin but also has been seen to produce cyclodepsipeptides and sporidemolides.

Habitat and ecology

''Pithomyces chartarum'' is more likely to be found in tropical locations but its range might be expanding. It can be found in pastures growing on debris and on damaged potato leaves, on dead leaves and stem of plants and occasionally in indoor environments on paper, ceiling tiles and may be present in carpet and mattress dust. It is thought to be especially frequent on fodder grasses. ''Pithomyces chartarum'' foliar infections can be clearly observed because they result in the formation of necrotic spots; however, recent studies have suggested that plant infections may be asymptomatic under certain circumstances. Growth of the fungus is inhibited ''in vitro'' by ''Bacillus subtilis'' and cochliodinol.

Disease

''Pithomyces chartarum'' is known to cause facial eczema in sheep and cattle, prevalent in

and occasionally in

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

. It is more common in sheep and deer, and goats seem to be less affected. Due to the growth required for the spores, we normally see cases occur after warm rains in fall or in summer. Symptoms of animal illness are usually apparent 10–14 days after ingestion. Animal disease caused by this fungus can be controlled in farm animals by avoiding short grazing, feeding cattle zinc or by using benzimidazole fungicides on pastures. The effects on human health are not well understood but it is thought that ''P. chartarum'' could also be involved in glue blotch disease of rice.

References

{{Taxonbar , from = Q41793778 Pleosporales