ARS | Publication request: Glucosylation and other biotransformations of T-2 toxin by yeasts of the Trichomonascus clade

Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 1, 2012
Publication Date: November 16, 2012
Citation: Mccormick, S.P., Price, N.P., Kurtzman, C.P. 2012. Glucosylation and other biotransformations of T-2 toxin by yeasts of the Trichomonascus clade. Applied and Environmental Microbiology. 78(24):8694-8702.

Interpretive Summary: Yeast species selected on the basis of predictions from phylogenetic analysis resulted in discovery of a way to efficiently produce a potentially less toxic metabolite called T-2 toxin 3-glucoside. T-2 toxin is a trichothecene mycotoxin produced by Fusarium in infected small grains, especially oats. Ingestion of T-2 toxin contaminated grain can result in a variety of symptoms including diarrhea, hemorrhaging and feed refusal. This study identified several yeast species that can convert T-2 toxin to other related compounds. One of the products, T-2 toxin 3-glucoside, has recently been identified as a masked mycotoxin in Fusarium infested grain. Masked mycotoxins are a potential food safety problem because they are not detected by current analytical methods. This study found an efficient way to produce T-2 toxin 3-glucoside that can be used to assess its toxicity and to develop new analytical methods for its detection and measurement.

Technical Abstract: Twenty-five yeasts assigned to the Trichomonascus clade (Saccharomycotina, Ascomycota), including three Trichomonascus species and 22 anamorphic species presently classified in Blastobotrys, were tested for their ability to convert T-2 toxin, a Fusarium trichothecene mycotoxin, to less toxic products. These species gave three types of biotransformations: acetylation to 3-acetyl T-2 toxin, glycosylation to T-2 toxin 3-glucoside, and removal of the isovaleryl group to form neosolaniol. Some species gave more than one type of biotransformation. Three Blastobotrys species converted T-2 toxin into T-2 toxin 3-glucoside, and this may be an efficient way to produce a compound that has been identified as a masked mycotoxin in Fusarium infected grain. This is the first report of a microbial whole cell method for producing trichothecene glycosides, and the resulting large-scale availability of T-2 toxin 3-glucoside will facilitate toxicity testing and development of methods for detection of this compound in agricultural and other products.