There were about 600 species in the genus in 2023 (although in 2008 the Dictionary of Fungi only listed 299[1][2]). They are ubiquitous in the environment and are a natural part of funga almost everywhere. They are normal agents of decay and decomposition. The spores 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.[2]
At least 20% of agricultural spoilage is caused by Alternaria species, with the most severe losses reaching 80% of yield.[2] Many human health disorders can be caused by these fungi, which grow on skin and mucous membranes, 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;[3] 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. Some species have also been reported as endophytic microorganisms with highly bioactive metabolites.[4]
^Kelman, MJ; Renaud, JB; Seifert, KA; Mack, J; Sivagnanam, K; Yeung, KK; Sumarah, MW (15 October 2015). "Identification of six new Alternaria sulfoconjugated metabolites by high-resolution neutral loss filtering". Rapid Commun Mass Spectrom. 29 (19): 1805–1810. Bibcode:2015RCMS...29.1805K. doi:10.1002/rcm.7286. PMID26331931.
^Karwehl S, Stadler M (July 2016). "Exploitation of fungal biodiversity for discovery of novel antibiotics". Current Topics in Microbiology and Immunology. 398: 303–338. doi:10.1007/82_2016_496. ISBN978-3-319-49282-7. PMID27422786.
^Ran Yuping (2016). "Observation of Fungi, Bacteria, and Parasites in Clinical Skin Samples Using Scanning Electron Microscopy". In Janecek, Milos; Kral, Robert (eds.). Modern Electron Microscopy in Physical and Life Sciences. InTech. doi:10.5772/61850. ISBN978-953-51-2252-4. S2CID53472683.
^Evans, N.; McRoberts, N.; Hill, R.A.; Marshall, G. (1996). "Phytotoxin production by Alternaria linicola and phytoalexin production by the linseed host". Ann. Appl. Biol. 129 (3): 415–431. doi:10.1111/j.1744-7348.1996.tb05765.x.
Other sources
Lawrence, DP; Park, MS; Pryor, BM (2012). "Nimbya and Embellisia revisited, with nov. comb. for Alternaria celosiae and A. perpunctulata". Mycological Progress. 11 (3): 799–815. doi:10.1007/s11557-011-0793-7. S2CID18225986.