Alternaria Species and Their Associated Mycotoxins

Abstract

The genus Alternaria includes more than 250 species. The traditional methods for identification of Alternaria species are based on morphological characteristics of the reproductive structures and sporulation patterns under controlled culture conditions. Cladistics analyses of "housekeeping genes" commonly used for other genera, failed to discriminate among the small-spored Alternaria species. The development of molecular methods achieving a better agreement with morphological differences is still needed. The production of secondary metabolites has also been used as a means of classification and identification. Alternaria spp. can produce a wide variety of toxic metabolites. These metabolites belong principally to three different structural groups: (1) the dibenzopyrone derivatives, alternariol (AOH), alternariol monomethyl ether (AME), and altenuene (ALT); (2) the perylene derivative altertoxins (ATX-I, ATX-II, and ATX II); and (3) the tetramic acid derivative, tenuazonic acid (TeA). TeA, AOH, AME, ALT, and ATX-I are the main. Certain species in the genus Alternaria produce host-specific toxins (HSTs) that contribute to their pathogenicity and virulence. Alternaria species are plant pathogens that cause spoilage of agricultural commodities with consequent mycotoxin accumulation and economic losses. Vegetable foods infected by Alternaria rot could introduce high amounts of these toxins to the human diet. More investigations on the toxic potential of these toxins and their hazard for human consumption are needed to make a reliable risk assessment of dietary exposure.

Isolation and Bioactivity of Secondary Metabolites from Solid Culture of the Fungus, Alternaria sonchi

“…Phytopathogenic fungi from the genus Alternaria are often considered as potential mycoherbicides [14][15][16][17] and producers of herbicidal molecules [3,18,19] as well as mycotoxins [20,21]. Alternaria sonchi J.J. Davis is a widely distributed leaf pathogen of sowthistles (Sonchus spp.)…”

Mycotoxin production of Alternaria strains isolated from Korean barley grains determined by LC-MS/MS

“…The most common Alternaria toxins found in cereals and food items are alternariol (AOH), alternariol monomethyl ether (AME), tentoxin (TEN), altenuene (ALT), and tenuazonic acid (TeA) (López et al,2014;Ostry, 2008;Patriarca et al, 2008). These toxins are classified into three different structural groups: (1) dibenzopyrone derivatives (AOH, AME, and ALT); (2) perylene-derived altertoxins (ATX-I, ATX-II, and ATX III); and (3) tetramic acid derivatives (TeA) (Pinto and Patriarca, 2017). Cereals can be infected by several species of genus Alternaria, particularly by A. alternata (Broggi et al, 2007;Azcarate et al, 2008;Xu et al, 2016).…”

Preliminary Survey of Alternaria Toxins Reduction during Fermentation of Whole Wheat Dough

“…These fungi are capable to produce a large number of different secondary metabolites-mycotoxins, which represent the most commonly occurring chemical contaminants of the cereal crops. Fungi of the genus Alternaria are considered as a group of ubiquitous plant pathogens, which can infect crops in the field, and saprophytic species, which can cause post-harvest decay of plant products [2,3], due to their tolerance to low temperature and water stress conditions, i.e., due to their environmental adaptability. Alternaria species produce more than 70 different mycotoxins, but the most relevant are tenuazonic acid (TeA), alternariol (AOH), alternariol monomethyl ether (AME), tentoxin (TEN), and altenuene (ALT) [4,5].…”