Alternaria tenuissima | |
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Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Fungi |
Division: | Ascomycota |
Class: | Dothideomycetes |
Order: | Pleosporales |
Family: | Pleosporaceae |
Genus: | Alternaria |
Species: | A. tenuissima |
Binomial name | |
Alternaria tenuissima Samuel Paul Wiltshire (1933) | |
Synonyms | |
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Alternaria tenuissima is a saprophytic fungus and opportunistic plant pathogen. It is cosmopolitan in distribution, and can colonize a wide range of plant hosts. [1] Colonies of A. tenuissima produce chains on agar growth media. [1] The fungus often forms concentric ring patterns on infected plant leaves. [2] This species produces the allergen Alt a 1, one of the most important outdoor seasonal fungal allergens associated with allergy and asthma provocation. [3] In rare circumstances, this species is also known to infect immunosuppressed humans and animals. [4]
Unlike many other species of Alternaria, the conidiophores of A. tenuissima can develop in darkness after the colony has been exposed to light even very briefly; however its growth is more robust with longer periods of light exposure. [5] After 5–7 days in culture, colonies of A. tenuissima reach a diameter of 5 cm on PCA or V-8 agar (vegetable juice agar). [1] Colonies grown on PCA are brown in colour with a loose, cottony texture and bearing golden-brown conidia in chains. [1] Conidia are on the areas of the colony that receive the most light exposure, forming concentric sporulating rings of uncrowded conidial chains growing from branching hyphae on PCA. [1] Sporulation tends to be much more crowded in colonies grown on V-8 agar. [1] Simple unbranched and branched conidial chains of moderate length as well as solitary conidia are interspersed across the colony especially areas that receive little light. [1]
The light, golden-brown colour of the conidia, and their tendency to taper into long beaks, distinguish A. tenuissima from similar species notably A. alternata which produces dark brown conidia with short beaks. [4] Conidia of A. tenuissima also grow individually or in short chains [6] of 2-5 units, [1] while A. alternata tends to grow in longer chains. [7] Alternaria tenuissima conidia are smooth-walled [6] and have a median and subconstricting transverse septum. [1] Colonies of A. tenuissima on natural substrates (e.g., plant leaves) often develop a concentric, ringed pattern. [2]
Alternaria tenuissima is a saprophyte, living on dead matter. [8] It produces the mycotoxins alternariol (AOH), alternariol methyl ester (AME), altenuene (ALT), altertoxin (ATX), and tenuazonic acid (TA), that are variously involved pathogenicity and interference competition. [8] Mycotoxins of this species are optimally produced at 25 °C. [9]
Alternaria tenuissima is a cosmopolitan species, common on an array of various plant hosts in many countries spanning a range of environmental conditions. [10] It often colonizes blueberries, [11] tomatoes, grapevine, and strawberries. [7] It has also been found on several cereal grain species. [8] Optimal growth occurs between 25–30 °C (77–86 °F). [12] Although A. tenuissima is normally an opportunistic pathogen of plants, rare cases of skin infections in immunocompromised people have been reported. [13] [14]
Cutaneous and subcutaneous alternariosis is a skin or tissue infection caused by members of the genus Alternaria, most commonly A. alternata and A. tenuissima. [4] Because of the inability of A. tenuissima to invade healthy host tissue, alternariosis tends to be restricted to people with abrogated cellular immunity and occasionally the elderly. [4] Complication following organ transplantion, Cushing's syndrome and immunosuppressive therapies are some of the typical settings in which alternariosis has been reported. [4] Alternariosis appears on the skin as red pustules that may produce ulcers over time. [4] Alternaria tenuissima is a prolific producer of the allergen Alt a 1. [15] Exposure to this protein can induce an allergic reaction in sensitized individuals by reacting with circulating IgE antibody. [3] Exposure to Alt a 1 has been associated with asthmatic exacerbation. [16] Alternaria tenuissima also produces the mycotoxin tenuazonic acid [17] which has received attention as a candidate antitumor medication. [18]
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.
House dust mites are various species of acariform mites belonging to the family Pyroglyphidae that are found in association with dust in dwellings. They are known for causing allergies.
Alternaria is a genus of Deuteromycetes fungi. All species are known as major plant pathogens. They are also common allergens in humans, growing indoors and causing hay fever or hypersensitivity reactions that sometimes lead to asthma. They are present in the human mycobiome and readily cause opportunistic infections in immunocompromised people such as AIDS patients.
Alternaria alternata is a fungus causing leaf spots, rots, and blights on many plant parts, and other diseases. It is an opportunistic pathogen on over 380 host species of plant.
Alternaria japonica is a fungal plant pathogen. It is a cause of black spot disease in cruciferous plants. It is not a major source of crop loss, but is considered dangerous for plants during the seedling stage.
Alternaria citri is a fungal plant pathogen that causes black rot in citrus plants.
Ulocladium is a genus of fungi. Species of this genus contain both plant pathogens and food spoilage agents. Other species contain enzymes that are biological control agents. Some members of the genus can invade homes and are a sign of moisture because the mold requires water to thrive. They can cause plant diseases or hay fever and more serious infections in immuno-suppressed individuals.
Aspergillus ochraceus is a mold species in the genus Aspergillus known to produce the toxin ochratoxin A, one of the most abundant food-contaminating mycotoxins, and citrinin. It also produces the dihydroisocoumarin mellein. It is a filamentous fungus in nature and has characteristic biseriate conidiophores. Traditionally a soil fungus, has now began to adapt to varied ecological niches, like agricultural commodities, farmed animal and marine species. In humans and animals the consumption of this fungus produces chronic neurotoxic, immunosuppressive, genotoxic, carcinogenic and teratogenic effects. Its airborne spores are one of the potential causes of asthma in children and lung diseases in humans. The pig and chicken populations in the farms are the most affected by this fungus and its mycotoxins. Certain fungicides like mancozeb, copper oxychloride, and sulfur have inhibitory effects on the growth of this fungus and its mycotoxin producing capacities.
Wallemia sebi is a xerophilic fungus of the phylum Basidiomycota.
Aspergillus versicolor is a slow-growing species of filamentous fungus commonly found in damp indoor environments and on food products. It has a characteristic musty odor associated with moldy homes and is a major producer of the hepatotoxic and carcinogenic mycotoxin sterigmatocystin. Like other Aspergillus species, A. versicolor is an eye, nose, and throat irritant.
Penicillium digitatum is a mesophilic fungus found in the soil of citrus-producing areas. It is a major source of post-harvest decay in fruits and is responsible for the widespread post-harvest disease in Citrus fruit known as green rot or green mould. In nature, this necrotrophic wound pathogen grows in filaments and reproduces asexually through the production of conidiophores and conidia. However, P. digitatum can also be cultivated in the laboratory setting. Alongside its pathogenic life cycle, P. digitatum is also involved in other human, animal and plant interactions and is currently being used in the production of immunologically based mycological detection assays for the food industry.
Epicoccum nigrum is a species of fungus in the phylum Ascomycota. A plant pathogen and endophyte, it is a widespread fungus which produces coloured pigments that can be used as antifungal agents against other pathogenic fungi. The fluorescent stain epicocconone is extracted from it.
Cladosporium cladosporioides is a darkly pigmented mold that occurs world-wide on a wide range of materials both outdoors and indoors. It is one of the most common fungi in outdoor air where its spores are important in seasonal allergic disease. While this species rarely causes invasive disease in animals, it is an important agent of plant disease, attacking both the leaves and fruits of many plants. This species produces asexual spores in delicate, branched chains that break apart readily and drift in the air. It is able to grow under low water conditions and at very low temperatures.
Cladosporium sphaerospermum is a radiotrophic fungus belonging to the genus Cladosporium and was described in 1886 by Albert Julius Otto Penzig from the decaying leaves and branches of Citrus. It is a dematiaceous (darkly-pigmented) fungus characterized by slow growth and largely asexual reproduction. Cladosporium sphaerospermum consists of a complex of poorly morphologically differentiated, "cryptic" species that share many physiological and ecological attributes. In older literature, all of these sibling species were classified as C. sphaerospermum despite their unique nature. Accordingly, there is confusion in older literature reports on the physiological and habitat regularities of C. sphaerospermum in the strict sense. This fungus is most phylogenetically similar to C. fusiforme. According to modern phylogenetic analyses, the previously synonymized species, Cladosporium langeroni, is a distinct species.
Ulocladium chartarum is an ascomycetes mushroom, one of the many in the genus Ulocladium.
Ulocladium botrytis is an anamorphic filamentous fungus belonging to the phylum Ascomycota. Commonly found in soil and damp indoor environments, U.botrytis is a hyphomycetous mould found in many regions of the world. It is also occasionally misidentified as a species of the genera Alternaria or Pithomyces due to morphological similarities. Ulocladium botrytis is rarely pathogenic to humans but is associated with human allergic responses and is used in allergy tests. Ulocladium botrytis has been implicated in some cases of human fungal nail infection. The fungus was first discovered in 1851 by German mycologist Carl Gottlieb Traugott Preuss.
Cladosporium herbarum is a common fungus found worldwide in organic and inorganic matter. It is efficiently distributed in the air, where it exists as the most frequently occurring fungal species. It can grow over a wide range of temperatures including very cold environments, giving it the ability to grow on refrigerated meat and form "black spots". Its high prevalence in the air and production of allergens makes C. herbarum an important exacerbant of asthma and hay fever.
Curvularia pallescens is a soil fungus, that commonly grows on crops found in tropical regions. The conidia of the fungus are distinguishable from those of related species due to their lack of curvature. C. pallescens has been reported to cause infection in plants, and in immunocompetent individuals. This species is the anamorph of Cochliobolus pallescens.
Alternaria brassicicola is a fungal necrotrophic plant pathogen that causes black spot disease on a wide range of hosts, particularly in the genus of Brassica, including a number of economically important crops such as cabbage, Chinese cabbage, cauliflower, oilseeds, broccoli and canola. Although mainly known as a significant plant pathogen, it also contributes to various respiratory allergic conditions such as asthma and rhinoconjunctivitis. Despite the presence of mating genes, no sexual reproductive stage has been reported for this fungus. In terms of geography, it is most likely to be found in tropical and sub-tropical regions, but also in places with high rain and humidity such as Poland. It has also been found in Taiwan and Israel. Its main mode of propagation is vegetative. The resulting conidia reside in the soil, air and water. These spores are extremely resilient and can overwinter on crop debris and overwintering herbaceous plants.
Alternaria leaf spot or Alternaria leaf blight are a group of fungal diseases in plants, that have a variety of hosts. The diseases infects common garden plants, such as cabbage, and are caused by several closely related species of fungi. Some of these fungal species target specific plants, while others have been known to target plant families. One commercially relevant plant genus that can be affected by Alternaria Leaf Spot is Brassica, as the cosmetic issues caused by symptomatic lesions can lead to rejection of crops by distributors and buyers. When certain crops such as cauliflower and broccoli are infected, the heads deteriorate and there is a complete loss of marketability. Secondary soft-rotting organisms can infect stored cabbage that has been affected by Alternaria Leaf Spot by entering through symptomatic lesions. Alternaria Leaf Spot diseases that affect Brassica species are caused by the pathogens Alternaria brassicae and Alternaria brassicicola.