''Brasiliomyces malachrae'' is a species of

fungus 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 ...

in the family Erysiphaceae. It is a

plant pathogen Plant pathology (also phytopathology) is the scientific study of diseases in plants caused by pathogens (infectious organisms) and environmental conditions (physiological factors). Organisms that cause infectious disease include fungi, oomyc ...

that grows on ''

Gossypium ''Gossypium'' () is a genus of flowering plants in the tribe Gossypieae of the mallow family, Malvaceae, from which cotton is harvested. It is native to tropical and subtropical regions of the Old and New Worlds. There are about 50 ''Gossypiu ...

'', '' Lavatera assurgentiflora'', '' Malachra capitata'', ''

Malvastrum coromandelianum ''Malvastrum coromandelianum'', also known as threelobe false mallow, is an annual or perennial herb or shrub native to North and South America. It has been introduced to many other areas of the world including Australia, Africa, and southern an ...

'', and species of ''

Malvaceae Malvaceae, or the mallows, is a family of flowering plants estimated to contain 244 genera with 4225 known species. Well-known members of economic importance include okra, cotton, cacao and durian. There are also some genera containing familiar ...

''. It is found in South America.

Taxonomy and phylogeny

''Brasiliomyces malachrae'' was named after its origin country of

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

and has the suffix "-myces" in the name. The suffix "-myces" is derived from the Greek "''mykēt-"'' meaning "mushroom". When discovered, it was found growing on ''Malvastrum coromandelianum,'' using it as a host . ''B. malchrae'' was first depicted in "''Scientific survey of porto rico and the Virgin Islands, vol. VIII, Part 1. Botany of Porto Rico and the Virgin Islands. Mycology''" authored by C.E. Chardon and J.F. Seaver. ''B. malchrae'' belongs to the genus

Brasiliomyces ''Brasiliomyces'' is a genus of fungi in the family Erysiphaceae Erysiphales are an order of ascomycete fungi. The order contains one family, Erysiphaceae. Many of them cause plant diseases called powdery mildew. Systematics The order conta ...

and is part of the family Erysiphaceae. Phylogenetic analysts using rRNA gene sequencing placed B. malachrae between the groups Golovinomyceteae and Erysiphe. It is closely related to ''B. chiangmaiensis, B. entadae, and B. setosus.''

Morphology

''Brasiliomyces malachrae'' forms white colonies made of superficial mycelium on its host's leaves. These colonies grow scattered along the surface of the foliage, giving it a powdery mildew appearance. ''B. malachrae'' is an

Ascomycota Ascomycota is a phylum of the kingdom Fungi that, together with the Basidiomycota, forms the subkingdom Dikarya. Its members are commonly known as the sac fungi or ascomycetes. It is the largest phylum of Fungi, with over 64,000 species. The def ...

species, which is characterized by having

ascospore An ascus (; ) is the sexual spore-bearing cell produced in ascomycete fungi. Each ascus usually contains eight ascospores (or octad), produced by meiosis followed, in most species, by a mitotic cell division. However, asci in some genera or s ...

s that are found within an

ascocarp An ascocarp, or ascoma (), is the fruiting body ( sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded asci, each of which typically contains four to eight ascospores. Ascocarps are m ...

. Powdery mildews form fruiting bodies known as chasmothecia (

cleistothecia An ascocarp, or ascoma (), is the fruiting body ( sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded asci, each of which typically contains four to eight ascospores. Ascocarps are ...

), which are considered

overwintering Overwintering is the process by which some organisms pass through or wait out the winter season, or pass through that period of the year when "winter" conditions (cold or sub-zero temperatures, ice, snow, limited food supplies) make normal activi ...

organs. These organs give the fungus an advantage by allowing it to survive during the winter season when temperatures drop making survival difficult or during a dry season when resources are limited. For this particular species, every cleistothecium contains sac-like, asci (singular:

ascus An ascus (; ) is the sexual spore-bearing cell produced in ascomycete fungi. Each ascus usually contains eight ascospores (or octad), produced by meiosis followed, in most species, by a mitotic cell division. However, asci in some genera or s ...

). Each asci contains 3-5 oval shaped ascospores with 5 being the most common. Brasiliomyces is distinguished from all other Erysiphales because of its "thin, semitransparent chasmothecia peridia" which is made of a single cell layer. In addition, it is ecologically unique for being the only species of powdery mildew that forms abundant ascocarps in tropical climates. ''B. malachrae'' has two sexual forms, the sexual and asexual morphs. The asexual morph is known to have hyaline ectophytic mycelium and catenescent conidia (singular: conidium). The mycelium for this morph is found present on the leaves, petioles and stems of plants. The sexual morph is known to form white chasmothecia which cover the surface of its host's leaves.

Ecology

''B. malachrae'' is an obligate biotroph of plants and is known to have 10,000 host species in

angiosperms Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

. It gets its energy and nutrients by parasitizing flowering plants related to false mallows (

) and

oak An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...

trees. Powdery mildews are plant pathogens known to cause polycyclic diseases which damage a plant's ability to photosynthesize. This type of infection causes a decrease in plant growth and an increase in the rate at which the host's tissues deteriorate. Its geographic distribution is subject to tropical areas, particularly in

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

. ''B. malachrae'' is found in abundance in areas of Brazil,

Venezuela Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in th ...

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

and

Puerto Rico Puerto Rico (; abbreviated PR; tnq, Boriken, ''Borinquen''), officially the Commonwealth of Puerto Rico ( es, link=yes, Estado Libre Asociado de Puerto Rico, lit=Free Associated State of Puerto Rico), is a Caribbean island and Unincorporated ...

Biology and relevance for humans

''Brasiliomyces malachrae'' has an economical impact on human life because it infects wild and cultivated cotton. Like other plant pathogens, powdery mildews cause significant decreases in crop yields and lowers the quality of the crops produced. It is unknown what other specific types of crops ''B. malachrae'' affects.

References

{{Taxonbar, from=Q4957831 Erysiphales Fungi described in 1926 Fungi of South America Fungal plant pathogens and diseases