Alternaria tenuissima | |
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Scientific classification
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Domain: | Eukaryota |
Kingdom: | Fungi |
Division: | Ascomycota |
Class: | Dothideomycetes |
Order: | Pleosporales |
Family: | Pleosporaceae |
Genus: | Alternaria |
Species: | A. tenuissima
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Binomial name | |
Alternaria tenuissima Samuel Paul Wiltshire (1933)
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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]
Alternaria tenuissima | |
---|---|
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 | |
|
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]