Fusarium graminearum

From MicrobeWiki, the student-edited microbiology resource

A Microbial Biorealm page on the genus Fusarium graminearum

Classification

Higher order taxa

Eukaryota; Fungi; Ascomycota

"F. graminearum macroconidia spore". http://microbewiki.kenyon.edu/images/6/6d/F._graminearum_macroconidia_spore.gif Courtesy of USDA ARS

Species

Fusarium graminearum

Description and significance

F. graminearum is commonly found on cereal grains, most commonly on wheat and barley. On wheat, the spores germinate on the kernel and grow down the stalk. Fruiting structures penetrate through the wheat's stomates. The kernels will appear visually "scabby".

"Fusarium head blight on wheat". Courtesy of USDA ARS

The macroconidia of F. graminearum are almost cylindrical in shape, with the central dorsal and ventral surfaces parallel. They most often contain five septa (Doyle and Beuchat, 2007) The end of the macroconidia are slightly bent in a "banana-like" formation with a foot cell or tiny knob at the tip.

F. graminearum, Fusarium Head Blight in particular, has major economic impacts. Diseased crop cost

Describe the appearance, habitat, etc. of the organism, and why you think it is important.

Genome structure

The genome of F. graminearum is made up of an assembly of plasmid, fosmid, and bacterial artificail chromosome, totaling 36.1 Mb and displaying high sequence quality and continuity. It is predicted that the genome contains a set of 11,640 genes and four chromosomes. Certain regions of the chromosomes have been found to have high levels of polymorphisms and high levels of recomination between strains of the species. An interesting feature of this observation is that genes that are specifically expressed during plant infection are all over-represented in high density single nucleotide polymorphic regions. The genome appears to have very few repetative sequences with fewer high-identity duplicates. It has been speculated that this is the result of repeat-induced point mutations.

Cell structure and metabolism

Interesting features of cell structure; how it gains energy; what important molecules it produces.


Ecology

Habitat; symbiosis; contributions to the environment.

Pathology

F. graminearum is best known as a plant pathogen. It causes various diseases of cereal grains, such as gibberella ear rot in corn and fusarium head blight or scab in wheat and other grains.

Toxic metabolites of the mold have been found to be toxigenic in humans. The major mycotoxins produced by F. graminearum are deoxynivalenol and zearalenone. Other toxins that may be produced by some strains include 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, diacetyldeoxynivalenol, butenolide, diacetoxyscirpenol, fusarenon-X, monoacetyoxyscirpenol, neosolaniol, nivalenol, or T-2 toxin (Marasas and others, 1984).


How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.


References

Cuomo, C., Guldener, U., Xu, J., Trail, F., Turgeon, B., Di Pietro, A., Walton, J., Ma, L., Baker, S., Rep, M., Adam, G., Antoniw, J., Baldwin, T., Calvo, S., Chang, Y., DeCaprio, D., Gale, L., Gnerre, S., Goswami, R., Hammond-Kosack, K., Harris, L., Hilburn, K., Kennell, J., Kroken, S., Magnuson, J., Mannhaupt, G., Munsterkotter, M., Nelson, D., O'Donnell, K., Ouellet, T., Qi, W., Quesneville, H., Roncero, M., Seong, K., Tetko, I., Urban, M., Waalwijk, C., Ward, T., Yao, J., Birren, B., Kistler, H. "The Fusarium graminearum Genome Reveals a Link Between Lacalized Polymorphism and Pathogen Specialization". Science. 2007. Vol. 317. p. 1400-1402.

Marasas, W.F.O., Nelson, P.E., Tousson, T.A. 1984. Toxigenic Fusarium Species: Identity and Mycotoxicology. The Pennsylvania State University Press, University Park, Pa.

Doyle, M.P., Beuchat, L.R., Food Microbiology: Fundamentals and Frontiers. 2007. ASM Press. Washington, DC.

Edited by student of Emily Lilly at University of Massachusetts Dartmouth.