Fusarium ear blight (FEB), is a fungal disease of cereals, including wheat, barley, oats, rye and triticale. FEB is caused by a range of Fusarium fungi, which infects the heads of the crop, reducing grain yield. The disease is often associated with contamination by mycotoxins produced by the fungi already when the crop is growing in the field. The disease can cause severe economic losses as mycotoxin-contaminated grain cannot be sold for food or feed.
Fusarium is a large genus of filamentous fungi, part of a group often referred to as hyphomycetes, widely distributed in soil and associated with plants. Most species are harmless saprobes, and are relatively abundant members of the soil microbial community. Some species produce mycotoxins in cereal crops that can affect human and animal health if they enter the food chain. The main toxins produced by these Fusarium species are fumonisins and trichothecenes. Despite most species apparently being harmless, some Fusarium species and subspecific groups are among the most important fungal pathogens of plants and animals.
Fumonisin B1 is the most prevalent member of a family of toxins, known as fumonisins, produced by multiple species of Fusarium molds, such as Fusarium verticillioides, which occur mainly in maize (corn), wheat and other cereals. Fumonisin B1 contamination of maize has been reported worldwide at mg/kg levels. Human exposure occurs at levels of micrograms to milligrams per day and is greatest in regions where maize products are the dietary staple.
Stachybotrys chartarum, also known as black mold or toxic black mold, is a species of microfungus that produces its conidia in slime heads.
Mycotoxicology is the branch of mycology that focuses on analyzing and studying the toxins produced by fungi, known as mycotoxins. In the food industry it is important to adopt measures that keep mycotoxin levels as low as practicable, especially those that are heat-stable. These chemical compounds are the result of secondary metabolism initiated in response to specific developmental or environmental signals. This includes biological stress from the environment, such as lower nutrients or competition for those available. Under this secondary path the fungus produces a wide array of compounds in order to gain some level of advantage, such as incrementing the efficiency of metabolic processes to gain more energy from less food, or attacking other microorganisms and being able to use their remains as a food source.
Stachybotrys is a genus of molds, hyphomycetes or asexually reproducing, filamentous fungi, now placed in the family Stachybotryaceae. The genus was erected by August Carl Joseph Corda in 1837. Historically, it was considered closely related to the genus Memnoniella, because the spores are produced in slimy heads rather than in dry chains. Recently, the synonymy of the two genera is generally accepted. Most Stachybotrys species inhabit materials rich in cellulose. The genus has a widespread distribution and contained about 50 species in 2008. There are 88 records of Stachybotrys on Species Fungorum, of which 33 species have DNA sequence data in GenBank. Species in the genus are commonly found in soil, plant litter and air and a few species have been found from damp paper, cotton, linen, cellulose-based building materials water-damaged indoor buildings, and air ducts from both aquatic and terrestrial habitats.
Fusarium culmorum is a fungal plant pathogen and the causal agent of seedling blight, foot rot, ear blight, stalk rot, common root rot and other diseases of cereals, grasses, and a wide variety of monocots and dicots. In coastal dunegrass, F. culmorum is a nonpathogenic symbiont conferring both salt and drought tolerance to the plant.
Gibberella zeae, also known by the name of its anamorph Fusarium graminearum, is a fungal plant pathogen which causes fusarium head blight (FHB), a devastating disease on wheat and barley. The pathogen is responsible for billions of dollars in economic losses worldwide each year. Infection causes shifts in the amino acid composition of wheat, resulting in shriveled kernels and contaminating the remaining grain with mycotoxins, mainly deoxynivalenol (DON), which inhibits protein biosynthesis; and zearalenone, an estrogenic mycotoxin. These toxins cause vomiting, liver damage, and reproductive defects in livestock, and are harmful to humans through contaminated food. Despite great efforts to find resistance genes against F. graminearum, no completely resistant variety is currently available. Research on the biology of F. graminearum is directed towards gaining insight into more details about the infection process and reveal weak spots in the life cycle of this pathogen to develop fungicides that can protect wheat from scab infection.
Crown rot of wheat is caused by the fungal pathogen Fusarium pseudograminearum. F. pseudograminearum is a member of the fungal phylum Ascomycota and is also known as Gibberella coronicola (teleomorph). It is a monoecious fungus, meaning it does not require another host other than wheat to complete its life cycle. Although F. pseudograminearum can produce both anamorphic and teleomorphic states, the teleomorph is usually not present for crown rot of wheat. This Fusarium species has, until recently, been considered to be the same as the species known as Fusarium graminearum due to many similar characteristics. One of the only differences between the two species is that F. pseudograminearum lacks its sexual stage on the wheat host.
Fusarium incarnatum is a fungal pathogen in the genus Fusarium, family Nectriaceae. It is usually associated with over 40 phylogenetic species in the natural environment to form the Fusarium incarnatum-equiseti species complex(FIESC). This complex is widespread across the globe in subtropical and temperate regions, resulting in many reported cases of crop diseases. It produces various mycotoxins including trichothecenes zearalenone, causing both plant and animal diseases.
Fusarium sporotrichioides is a fungal plant pathogen, one of various Fusarium species responsible for damaging crops, in particular causing a condition known as Fusarium head blight in wheat, consequently being of notable agricultural and economic importance. The species is ecologically widespread, being found across tropical and temperate regions, and is a significant producer of mycotoxins, particularly trichothecenes. Although mainly infecting crops, F. sporotrichioides-derived mycotoxins can have repercussions for human health in the case of the ingestion of infected cereals. One such example includes the outbreak of alimentary toxic aleukia (ATA) in Russia, of which F. sporotrichioides-infected crop was suspected to be the cause. Although current studies on F. sporotrichioides are somewhat limited in comparison to other species in the genus, Fusarium sporotrichioides has found several applications as a model system for experimentation in molecular biology.
Fusarium equiseti is a fungal species and plant pathogen on a varied range of crops.
Fusarium verticillioides is the most commonly reported fungal species infecting maize. Fusarium verticillioides is the accepted name of the species, which was also known as Fusarium moniliforme. The species has also been described as mating population A of the Fusarium fujikuroi species complex. F. verticllioides produces the mutagenic chemical compound fusarin C. F. verticillioides produces a group of disease-causing mycotoxins—fumonisins—on infected kernels.
Fusarium crookwellense is a species of fungus in the family Nectriaceae. It is known as a plant pathogen that infects agricultural crops.
Vomitoxin, also known as deoxynivalenol (DON), is a type B trichothecene, an epoxy-sesquiterpenoid. This mycotoxin occurs predominantly in grains such as wheat, barley, oats, rye, and corn, and less often in rice, sorghum, and triticale. The occurrence of deoxynivalenol is associated primarily with Fusarium graminearum and F. culmorum, both of which are important plant pathogens which cause fusarium head blight in wheat and gibberella or fusarium ear blight in corn. The incidence of fusarium head blight is strongly associated with moisture at the time of flowering (anthesis), and the timing of rainfall, rather than the amount, is the most critical factor. However, increased amount of moisture towards harvest time has been associated with lower amount of vomitoxin in wheat grain due to leaching of toxins. Furthermore, deoxynivalenol contents are significantly affected by the susceptibility of cultivars towards Fusarium species, previous crop, tillage practices, and fungicide use. It occurs abundantly in grains in Norway due to heavy rainfall.
Many species of fungi produce secondary metabolites called mycotoxins. These toxins can be very detrimental to both humans and animals. The side-effects of ingesting these toxic substances are called mycotoxicosis, which can be a variety of medical conditions. The most common fungi that produce mycotoxins include Fusarium, Aspergillus, and Penicillium.
β-Zearalenol is a nonsteroidal estrogen of the resorcylic acid lactone group related to mycoestrogens found in Fusarium spp. It is the β epimer of α-zearalenol and along with α-zearalenol is a major metabolite of zearalenone formed mainly in the liver but also to a lesser extent in the intestines during first-pass metabolism. A relatively high proportion of α-zearalenol is formed from zearalenone compared to β-zearalenol in humans. β-Zearalenol is about the same or slightly less potent as an estrogen relative to zearalenone.
Fusarins are a class of mycotoxins produced mainly by fungi of the genus Fusarium, which can infect agriculturally important crops such as wheat, barley, oats, rye, and corn. Chemically, they are polyketides that are also derived from amino acids.
Fumonisin B4 is a fumonisin mycotoxin produced mainly by the fungi Fusarium proliferatum, Fusarium verticillioides. Recently FB4 has been detected in fungi Aspergillus niger and in several Tolypocladium species.
