''Helicobasidium longisporum'' is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

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

in the

subdivision Subdivision may refer to: Arts and entertainment * Subdivision (metre), in music * ''Subdivision'' (film), 2009 * "Subdivision", an episode of ''Prison Break'' (season 2) * ''Subdivisions'' (EP), by Sinch, 2005 * "Subdivisions" (song), by Rush ...

Pucciniomycotina Pucciniomycotina is a subdivision of fungus within the division Basidiomycota. The subdivision contains 10 classes, 21 orders, and 38 families. Over 8400 species of Pucciniomycotina have been described - more than 8% of all described fungi. T ...

Basidiocarps 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 no ...

(fruit bodies) are

corticioid The corticioid fungi are a group of fungi in the Basidiomycota typically having effused, smooth basidiocarps (fruit bodies) that are formed on the undersides of dead tree trunks or branches. They are sometimes colloquially called crust fungi or pa ...

(patch-forming) and are typically violet to purple. Microscopically they have auricularioid (laterally septate)

basidia A basidium (: basidia) is a microscopic spore-producing structure found on the hymenophore of reproductive bodies of basidiomycete fungi. The presence of basidia is one of the main characteristic features of the group. These bodies are also ...

. ''Helicobasidium longisporum'' is an opportunistic

plant pathogen Plant diseases are diseases in plants caused by pathogens (infectious organisms) and environmental conditions (physiological factors). Organisms that cause infectious disease include fungi, oomycetes, bacteria, viruses, viroids, virus-like orga ...

and is one of the causes of violet root rot of crops and other plants. DNA sequencing suggests that it is a

complex Complex commonly refers to: * Complexity, the behaviour of a system whose components interact in multiple ways so possible interactions are difficult to describe ** Complex system, a system composed of many components which may interact with each ...

of more than one species.

Taxonomy

''Helicobasidium longisporum'' was first described from Uganda in 1917 by British

mycologist Mycology is the branch of biology concerned with the study of fungi, including their taxonomy, genetics, biochemical properties, and use by humans. Fungi can be a source of tinder, food, traditional medicine, as well as entheogens, poison, and ...

Elsie Wakefield to accommodate a species similar to ''

Helicobasidium purpureum ''Helicobasidium'' is a genus of fungi in the subdivision Pucciniomycotina. Basidiocarps (fruit bodies) are corticioid (patch-forming) and are typically violet to purple. Microscopically they have auricularioid (laterally septate) basidia. Asexua ...

'' but with elongated

basidiospores A basidiospore is a reproductive spore produced by basidiomycete fungi, a grouping that includes mushrooms, shelf fungi, rusts, and smuts. Basidiospores typically each contain one haploid nucleus that is the product of meiosis, and they are pr ...

. It was found parasitizing roots of cocoa (''

Theobroma cacao ''Theobroma cacao'' (cacao tree or cocoa tree) is a small ( tall) evergreen tree in the Malvaceae family. Its seedscocoa beansare used to make chocolate liquor, cocoa solids, cocoa butter and chocolate. Although the tree is native to the tropi ...

''). A similarly long-spored Japanese taxon was described as ''H. mompa'' f. ''macrosporum'' and a further long-spored species was subsequently described from Indonesia as ''H. compactum''. All three were considered conspecific in a 1999 study. In 1955 Japanese mycologist Seiya Ito synonymized ''H. mompa'' f. ''macrosporum'' and ''H. compactum'' with a short-spored species, '' Helicobasidium mompa''. As a result, at least some subsequent references to ''H. mompa'' refer to a long—spored species. Initial

molecular A molecule is a group of two or more atoms that are held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions that satisfy this criterion. In quantum physics, organic chemistry, ...

research, based on

cladistic Cladistics ( ; from Ancient Greek 'branch') is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is ...

analysis of

DNA sequences A nucleic acid sequence is a succession of bases within the nucleotides forming alleles within a DNA (using GACT) or RNA (GACU) molecule. This succession is denoted by a series of a set of five different letters that indicate the order of the ...

, indicates that at least two species occur in the ''H.longisporum'' complex, one in Europe (together with its '' Tuberculina''

anamorph In mycology, the terms teleomorph, anamorph, and holomorph apply to portions of the life cycles of fungi in the phyla Ascomycota and Basidiomycota: *Teleomorph: the sexual reproductive stage (morph), typically a fruiting body. *Anamorph: an ase ...

) and one in Africa and the Americas (also with its anamorph).

Description

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 no ...

s are

smooth, membranaceous, purple to purple-brown. Microscopically the

hyphae A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one o ...

are easily visible, 5–8 μm diam., brownish-purple, and lack

clamp connection A clamp connection is a hook-like structure formed by growing hyphal cells of certain fungi. It is a characteristic feature of basidiomycete fungi. It is created to ensure that each cell, or segment of hypha separated by septa (cross walls), rece ...

Basidia A basidium (: basidia) is a microscopic spore-producing structure found on the hymenophore of reproductive bodies of basidiomycete fungi. The presence of basidia is one of the main characteristic features of the group. These bodies are also ...

are tubular, curved or crook-shaped, and auricularioid (laterally septate).

Basidiospores A basidiospore is a reproductive spore produced by basidiomycete fungi, a grouping that includes mushrooms, shelf fungi, rusts, and smuts. Basidiospores typically each contain one haploid nucleus that is the product of meiosis, and they are pr ...

are elongated clavate, mostly 16–25 x 4.5–6 μm.

Distribution

''Helicobasidium longisporum'' has been recorded from both temperate and tropical areas of Africa, America, Asia, Australia, and Europe. It is reported to cause violet root rot of various crops and a similar collar rot or collar canker of coffee trees.

References

{{DEFAULTSORT:Helicobasidium Longisporum Fungal plant pathogens and diseases Fungi described in 1917 Fungi of Africa Pucciniomycotina Fungus species