Engineering deoxynivalenol metabolism in wheat through the expression of a fungal trichothecene acetyltransferase gene

Okubara, Patricia A.; Blechl, Ann E.; McCormick, Susan P.; Alexander, Nancy J.; Dill‐Macky, Ruth; Höhn, Thomas

doi:10.1007/s00122-002-1066-2

Cited by 119 publications

(62 citation statements)

References 38 publications

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“…In a recent investigation, constitutive (over)expression of trichothecene 3-O-acetyltransferase in wheat conferred partial protection against spread of scab in greenhouse tests (32). Transformants of cv.…”

Section: Discussionmentioning

confidence: 99%

Infection patterns in barley and wheat spikes inoculated with wild-type and trichodiene synthase gene disrupted Fusarium graminearum

Jansen

Wettstein

Schäfer

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

559

479

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Fusarium head blight epidemics of wheat and barley cause heavy economic losses to farmers due to yield decreases and production of mycotoxin that renders the grain useless for flour and malt products. No highly resistant cultivars are available at present. Hyphae of germinating fungal spores use different paths of infection: After germination at the extruded tip of an ovary, the hyphae travel along the epicarp in the space between the lemma and palea. Infection of the developing kernel proceeds through the epicarp, successively destroying the layers of the fruit coat and finally the starch and protein accumulating endosperm. Hyphae reaching the rachis proceed to apically located developing kernels. Using a constitutively green fluorescence protein-expressing Fusarium wild-type strain, and its knockout mutant, preventing trichothecene synthesis, we demonstrate that trichothecenes are not a virulence factor during infection through the fruit coat. In the absence of trichothecenes, the fungus is blocked by the development of heavy cell wall thickenings in the rachis node of Nandu wheat, a defense inhibited by the mycotoxin. In barley hyphae of both wild-type and the trichothecene knockout mutant, are inhibited at the rachis node and rachilla, limiting infection of adjacent florets through the phloem and along the surface of the rachis. Effective resistance to Fusarium head blight requires expression of genes that combat these different pathways of infection.

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Section: Discussionmentioning

confidence: 99%

Infection patterns in barley and wheat spikes inoculated with wild-type and trichodiene synthase gene disrupted Fusarium graminearum

Jansen

Wettstein

Schäfer

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

559

479

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“…The protein FsTRI101 transfers acetyl groups to the C3 hydroxyl group of trichothecenes, which includes DON. A gene from F. sporotrichoides (FsTRI101) that codes for FsTRI101 was transformed into wheat and shown to provide protection against FHB (Okubara et al, 2002).…”

Section: Standard Data Requirements and Case-by-case Risk Assessmentsmentioning

confidence: 99%

Problem formulation and hypothesis testing for environmental risk assessments of genetically modified crops

Raybould

2006

Environ. Biosafety Res.

124

137

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Environmental risk assessments can provide high confidence of minimal risk by testing theories, "risk hypotheses", that predict the likelihood of unacceptable harmful events. The creation of risk hypotheses and a plan to test them is called problem formulation. Effective problem formulation seeks to maximize the possibility of detecting effects that indicate potential risk; if such effects are not detected, minimal risk is indicated with high confidence. Two important implications are that artificial test conditions can increase confidence, whereas prescriptive data requirements can reduce confidence (increase uncertainty) if they constrain problem formulation. Poor problem formulation can increase environmental risk because it leads to the collection of superfluous data that may delay or prevent the introduction of environmentally beneficial products.

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“…These microbes can also be a source of genes that can be used to engineer disease-resistant crop plants. For example, the trichothecene acetyltransferase gene has been used to confer resistance to DON (33), which is a major virulence factor in Fusarium graminearum wheat head blight disease (37).…”

mentioning

confidence: 99%

Glucosylation and Other Biotransformations of T-2 Toxin by Yeasts of the Trichomonascus Clade

McCormick

Price

Kurtzman

2012

Appl Environ Microbiol

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bTrichothecenes are sesquiterpenoid toxins produced by Fusarium species. Since these mycotoxins are very stable, there is interest in microbial transformations that can remove toxins from contaminated grain or cereal products. Twenty-three yeast species assigned to the Trichomonascus clade (Saccharomycotina, Ascomycota), including four Trichomonascus species and 19 anamorphic species presently classified in Blastobotrys, were tested for their ability to convert the trichothecene T-2 toxin 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, 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 potential 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.T he fungal T-2 toxin (see Fig. 1) is a sesquiterpenoid trichothecene produced by Fusarium sporotrichioides and related species. Trichothecenes inhibit protein synthesis in eukaryotes and can cause both acute and chronic health problems for humans and animals that ingest contaminated food or feed. T-2 toxin in overwintered wheat was the cause of outbreaks of alimentary toxic aleukia in the 1930s in the former Soviet Union and has been associated with other gastrointestinal problems (42).Trichothecenes are very stable mycotoxins. Consequently, there is interest in identifying chemical treatments or microbial transformations that effectively remove the compounds from contaminated grain or cereal products. For example, treatment of contaminated grain with the preservative sodium bisulfite converts the trichothecene deoxynivalenol (DON) into nontoxic DON sulfonates (13). Several types of microbial bioconversions of trichothecenes have also been reported (49), including oxygenation (3), acetylation (1, 24), deacetylation (5, 47), oxidation (41), deepoxidation (16, 20, 25, 43, 44, 48), and epimerization (19, 22). Some of these transformations lead to a complete loss of toxicity of the trichothecenes (e.g., deepoxidation) or reduce their toxicity (e.g., acetylation, oxidation) and thereby protect organisms from the deleterious effects of the toxins. Changes to the C-3 position and the epoxide have the greatest impact on toxicity (49). Indeed, microbes or enzymes that degrade or detoxify mycotoxins have possible practical applications as additives in animal feeds. These microbes can also be a source of genes that can be used to engineer disease-resistant crop plants. For example, the trichothecene acetyltransferase gene has been used to confer resistance to DON (33), which is a major virulence factor in Fusarium graminearum whe...

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Engineering deoxynivalenol metabolism in wheat through the expression of a fungal trichothecene acetyltransferase gene

Cited by 119 publications

References 38 publications

Infection patterns in barley and wheat spikes inoculated with wild-type and trichodiene synthase gene disrupted Fusarium graminearum

Infection patterns in barley and wheat spikes inoculated with wild-type and trichodiene synthase gene disrupted Fusarium graminearum

Problem formulation and hypothesis testing for environmental risk assessments of genetically modified crops

Glucosylation and Other Biotransformations of T-2 Toxin by Yeasts of the Trichomonascus Clade

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