Title: Fusarium Mycotoxins: Biosynthetic Pathways and Role in Virulence Authors
|Harris, L -|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: November 4, 2009
Publication Date: November 4, 2009
Citation: Alexander, N.J., Mccormick, S.P., Harris, L.J. 2009. Fusarium Mycotoxins: Biosynthetic Pathways and Role in Virulence [abstract]. Canadian Workshop on Fusarium Head Blight. Technical Abstract: Fusarium head blight (FHB) of wheat and barley is a devastating disease that has reached global proportions. Not only does this disease result in lower yields, but the mycotoxins produced by the fungus affect the quality of the grain. Fusarium sp. can produce a number of mycotoxins, including trichothecenes, butenolide, culmorin, enniatins, and zearalenone. The trichothecenes most commonly found in infested grain are deoxynivalenol (DON) and nivalenol (NIV), the former of which has been identified as a virulence factor for FHB. The identification of genes involved in the formation of trichothecenes has lead to the description of a complex biosynthetic pathway. The physical location of the genes involves at least three chromosomes yet expression of many of the toxin biosynthetic genes is coordinated by the products of at least two genes located within the core cluster of twelve genes. The identification of genes involved in the formation of butenolide and culmorin has been aided by the production of expressed sequence tag (EST) libraries. Searching the libraries for genes expressed at high levels during mycotoxin formation provided a number of candidate genes. Gene knock-out studies, as well as transgenic expression studies, provided the proof of function of these genes. Culmorin has been detected in wheat seed, especially European wheat that is infected with F. culmorum, but it is not known if or how it relates to FHB. Studies are underway to determine if culmorin and/or butenolide are virulence factors for FHB.