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 existing on the skin as commensal members of the skin flora), some Fusarium species and subspecific groups are among the most important fungal pathogens of plants and animals. The name of Fusarium comes from Latin fusus, meaning a spindle. Taxonomy The taxonomy of the genus is complex. A number of different schemes have been used, and up to 1,000 species have been identified at times, with approaches varying between wide and narrow concepts of speciation (lumpers and splitters). Phylogenetic studies indicate seven major clades within the genus. There is a proposed conceptwidely subscribed by specialiststhat would include essentially the genus as it now stands, including especially all agriculturally significant Fusaria. There is a counterproposal (unrelated to ) that goes far in the other direction, with seven entirely new genera. Subdivision Various schemes have subdivided the genus into subgenera and sections. There is a poor correlation between sections and phylogenetic clades. Sections previously described include: Arachnites Arthrosporiella Discolour Elegans Eupionnotes Gibbosum Lateritium Liseola Martiella Ventricosum Roseum Spicarioides Sporotrichiella Species Selected species include: Fusarium acaciae Fusarium fujikuroi Fusarium acaciae-mearnsii Fusarium acutatum Fusarium aderholdii Fusarium acremoniopsis Fusarium affine Fusarium arthrosporioides Fusarium avenaceum Fusarium bubigeum Fusarium circinatum Fusarium crookwellense Fusarium culmorum Fusarium graminearum Fusarium incarnatum Fusarium langsethiae Fusarium mangiferae Fusarium merismoides Fusarium oxysporum Fusarium pallidoroseum Fusarium poae Fusarium proliferatum Fusarium pseudograminearum Fusarium redolens Fusarium sacchari Fusarium solani Fusarium sporotrichioides Fusarium sterilihyphosum Fusarium subglutinans Fusarium sulphureum Fusarium tricinctum Fusarium udum Fusarium venenatum Fusarium verticillioides Fusarium virguliforme Fusarium xyrophilum Etymology The name of Fusarium comes from Latin fusus, meaning a spindle. Pathogen The genus includes a number of economically important plant pathogenic species. Fusarium graminearum commonly infects barley if there is rain late in the season. It is of economic impact to the malting and brewing industries, as well as feed barley. Fusarium contamination in barley can result in head blight, and in extreme contaminations, the barley can appear pink. The genome of this wheat and maize