''Alternaria'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of Deuteromycetes fungi. All species are known as major plant pathogens. They are also common

allergen An allergen is a type of antigen that produces an abnormally vigorous immune response in which the immune system fights off a perceived threat that would otherwise be harmless to the body. Such reactions are called allergies. In technical t ...

s in humans, growing indoors and causing

hay fever Allergic rhinitis, of which the seasonal type is called hay fever, is a type of inflammation in the nose that occurs when the immune system overreacts to allergens in the air. Signs and symptoms include a runny or stuffy nose, sneezing, red, i ...

or hypersensitivity reactions that sometimes lead to

asthma Asthma is a long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wheezing, co ...

. They are present in the human mycobiome and readily cause

opportunistic infection An opportunistic infection is an infection caused by pathogens (bacteria, fungi, parasites or viruses) that take advantage of an opportunity not normally available. These opportunities can stem from a variety of sources, such as a weakened immun ...

s in immunocompromised people such as

AIDS Human immunodeficiency virus infection and acquired immunodeficiency syndrome (HIV/AIDS) is a spectrum of conditions caused by infection with the human immunodeficiency virus (HIV), a retrovirus. Following initial infection an individual ma ...

patients. There are 299 species in the genus; they are ubiquitous in the environment and are a natural part of fungal flora almost everywhere. They are normal agents of decay and

decomposition Decomposition or rot is the process by which dead organic substances are broken down into simpler organic or inorganic matter such as carbon dioxide, water, simple sugars and mineral salts. The process is a part of the nutrient cycle and ...

. The

spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, ...

s are airborne and found in the soil and water, as well as indoors and on objects. The club-shaped spores are single or form long chains. They can grow thick colonies which are usually green, black, or gray. At least 20% of

agricultural Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled peopl ...

spoilage is caused by ''Alternaria'' species, with the most severe losses reaching 80% of yield. Many human health disorders can be caused by these fungi, which grow on skin and

mucous membrane A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It i ...

s, including on the eyeballs and within the respiratory tract. Allergies are common, but serious infections are rare, except in people with compromised immune systems. However, species of this fungal genus are often prolific producers of a variety of toxic compounds. The effects most of these compounds have on animal and plant health are not well known. Many species of alternaria modify their secondary metabolites by sulfoconjugation; however, the role of this process is not yet understood. The terms '' alternariosis'' and ''alternariatoxicosis'' are used for disorders in humans and animals caused by a fungus in this genus. Not all ''Alternaria'' species are pests and pathogens; some have shown promise as biocontrol agents against

invasive plant species An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species ad ...

. Some species have also been reported as endophytic microorganisms with highly bioactive metabolites. The genus is now known to be

polyphyletic A polyphyletic group is an assemblage of organisms or other evolving elements that is of mixed evolutionary origin. The term is often applied to groups that share similar features known as homoplasies, which are explained as a result of conver ...

Species

Some species include: *'' Alternaria alternata'' – Causes early blight of potato, Leaf spot disease in '' Withania somnifera'' and can infest many other plants. It also causes upper respiratory infections in AIDS patients, asthma in people with sensitivity, and has been implicated in chronic rhinosinusitis. *'' Alternaria alternantherae'' *'' Alternaria arborescens'' – causes stem canker of

tomato The tomato is the edible berry of the plant ''Solanum lycopersicum'', commonly known as the tomato plant. The species originated in western South America, Mexico, and Central America. The Mexican Nahuatl word gave rise to the Spanish word ...

*'' Alternaria arbusti'' – causes leaf lesions on

Asian pear Fruit commonly known as the Asian pear in different parts of the world include: * ''Pyrus pyrifolia ''Pyrus pyrifolia'' is a species of pear tree native to East Asia. The tree's edible fruit is known by many names, including: Asian pear, Jap ...

*'' Alternaria blumeae'' – causes lesions on ''Blumea aurita'' *'' Alternaria brassicae'' – infests many vegetables and roses *'' Alternaria brassicicola'' – grows on

cole crops Cruciferous vegetables are vegetables of the family Brassicaceae (also called Cruciferae) with many genera, species, and cultivars being raised for food production such as cauliflower, cabbage, kale, garden cress, bok choy, broccoli, Brussels sp ...

*'' Alternaria burnsii'' – causing cumin blossom blight *'' Alternaria carotiincultae'' – causes leaf blight on

carrot The carrot ('' Daucus carota'' subsp. ''sativus'') is a root vegetable, typically orange in color, though purple, black, red, white, and yellow cultivars exist, all of which are domesticated forms of the wild carrot, ''Daucus carota'', na ...

*'' Alternaria carthami'' *'' Alternaria celosiae'' *'' Alternaria cinerariae'' *''

Alternaria citri ''Alternaria citri'' is a fungal plant pathogen that causes black rot in citrus plants. Host and symptoms ''Alternaria citri'' is an ascomycete fungal plant pathogen that causes black rot in citrus plants. Specifically, certain lemon, lime, or ...

'' – causes black rot on

citrus ''Citrus'' is a genus of flowering trees and shrubs in the rue family, Rutaceae. Plants in the genus produce citrus fruits, including important crops such as oranges, lemons, grapefruits, pomelos, and limes. The genus ''Citrus'' is native to ...

plants *'' Alternaria conjuncta'' – grows on parsnip *'' Alternaria cucumerina'' – grows on various cucurbits *'' Alternaria dauci'' – grows on carrot *'' Alternaria dianthi'' *'' Alternaria dianthicola'' *'' Alternaria eichhorniae'' – infests

water hyacinth ''Pontederia crassipes'' (formerly ''Eichhornia crassipes''), commonly known as common water hyacinth is an aquatic plant native to South America, naturalized throughout the world, and often invasive outside its native range.Alternaria euphorbiicola'' – infests cole crops *'' Alternaria eureka'' *'' Alternaria gaisen'' – causes ringspot disease of pear *'' Alternaria helianthi'' *'' Alternaria helianthicola'' *'' Alternaria hungarica'' *'' Alternaria infectoria'' – infests

wheat Wheat is a grass widely cultivated for its seed, a cereal grain that is a worldwide staple food. The many species of wheat together make up the genus ''Triticum'' ; the most widely grown is common wheat (''T. aestivum''). The archaeologi ...

*'' Alternaria japonica'' – infests cole crops *'' Alternaria limicola'' – earliest diverging lineage of Section Porri *'' Alternaria linicola'' *'' Alternaria longipes'' – infects tobacco *'' Alternaria mali'' *'' Alternaria molesta'' – may cause skin lesions on

porpoise Porpoises are a group of fully aquatic marine mammals, all of which are classified under the family Phocoenidae, parvorder Odontoceti (toothed whales). Although similar in appearance to dolphins, they are more closely related to narwhals a ...

s *'' Alternaria panax'' – causes ginseng blight *'' Alternaria perpunctulata'' *'' Alternaria petroselini'' – causes

parsley Parsley, or garden parsley (''Petroselinum crispum'') is a species of flowering plant in the family Apiaceae that is native to the central and eastern Mediterranean region (Sardinia, Lebanon, Israel, Cyprus, Turkey, southern Italy, Greece, ...

leaf blight *'' Alternaria porri'' *'' Alternaria quercicola'' *'' Alternaria radicina'' – causes carrot decay *'' Alternaria raphani'' *'' Alternaria saponariae'' *'' Alternaria selini'' – causes parsley crown decay *'' Alternaria senecionis'' *'' Alternaria solani'' – causes

early blight ''Alternaria solani'' is a fungal pathogen that produces a disease in tomato and potato plants called early blight. The pathogen produces distinctive "bullseye" patterned leaf spots and can also cause stem lesions and fruit rot on tomato and ...

in potatoes and tomatoes *'' Alternaria smyrnii'' – infests

alexanders ''Smyrnium olusatrum'', common name alexanders (or alisander) is an edible flowering plant of the family Apiaceae (Umbelliferae), which grows on waste ground and in hedges around the Mediterranean and Atlantic coastal regions of Europe. It was ...

and parsleys *'' Alternaria tenuissima'' *'' Alternaria triticina'' *'' Alternaria ventricosa'' *'' Alternaria zinniae''

References

Other sources

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External links

''Alternaria'' as an indoor fungal allergen

Alternaria Online
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Mycology Online page

{{Taxonbar, from=Q133266 Dothideomycetes genera Fungal plant pathogens and diseases