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ARS Home » Midwest Area » Peoria, Illinois » National Center for Agricultural Utilization Research » Mycotoxin Prevention and Applied Microbiology Research » Research » Publications at this Location » Publication #304216
Title: Production of a new type A trichothecene by isolates of Fusarium graminearum

Author
item WIESENBERGER, GERLINDE - University Of Natural Resources & Applied Life Sciences - Austria
item VARGA, ELISABETH - University Of Natural Resources & Applied Life Sciences - Austria
item HAMETNER, CHRISTIAN - Vienna University Of Technology
item STUCKLER, ROMANA - University Of Natural Resources & Applied Life Sciences - Austria
item KISTLER, CORBY - University Of Minnesota
item Ward, Todd
item SCHOFBECK, DENISE - University Of Natural Resources & Applied Life Sciences - Austria
item SULYOK, MICHAEL - University Of Natural Resources & Applied Life Sciences - Austria
item KRSKA, RUDOLF - University Of Natural Resources & Applied Life Sciences - Austria
item SCHUHMACHER, RAINER - University Of Natural Resources & Applied Life Sciences - Austria
item BERTHILLER, FRANZ - University Of Natural Resources & Applied Life Sciences - Austria
item ADAM, GERHARD - Vienna University Of Technology

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 11/12/2014
Publication Date: 11/12/2014
Citation: Wiesenberger, G., Varga, E., Hametner, C., Stuckler, R., Kistler, C.H., Ward, T.J., Schofbeck, D., Sulyok, M., Krska, R., Schuhmacher, R., Berthiller, F., Adam, G. 2014. Production of a new type A trichothecene by isolates of Fusarium graminearum [abstract]. World Mycotoxin Forum.

Interpretive Summary:

Technical Abstract: Production of deoxynivalenol (DON) is a virulence factor of Fusarium graminearum on wheat and most likely on other host plants. A large survey of F. graminearum (sensu strictu) in the northern United States revealed the existence of strains which - based on molecular markers - belong to the 3-acetyl-DON (ADON) chemotype, but do not produce known DON or nivalenol derivatives. With a LC-MS/MS multitoxin method we confirmed that the isolates do not produce known trichothecenes. Yet, GC-MS headspace analysis revealed presence of the precurser trichodiene. A compound occurring in the “Northland” (N) strains was purified and its structure elucidated. The novel trichothecene, termed NX2, is identical to 3-ADON with the exception that it lacks the keto group at C-8, which is a hallmark of the typical type B trichothecenes. During colonisation of wheat the new toxin NX2 is deactylated to DNX2, like 3-ADON to DON. The toxicity of DNX2 is very similar to that of DON in two plant and animal derived in vitro translation systems (wheat germ extract, rabbit reticulocyte lysate). We have started to investigate the molecular basis of NX2 production. The TRI1 gene product introduces an oxygen function only at C8 in F. sporotrichioides, while it is is responsible for both the C7 and C8 oxygenation in normal F. graminearum strains. We are testing the following hypotheses: Either the TRI1 gene in N strains is non-functional and the oxygenation at C7 is performed by a different cytochrome P450 oxygenase, or, a modified TRI1 product of NX-2 producing strains might hydroxylate at C7 only. We found 14 amino-acid changes in all N strains investigated compared to the sequenced strain PH-1. Inactivation of the TRI1 gene in an N strain led to production of trace amounts of NX2. To test whether the N-allele of TRI1 is responsible for NX2 production we have swapped the TRI1 alleles of PH-1 and N-strains. It is unclear at present how prevalent and toxicologically relevant this new mycotoxin is, which escapes conventional detection techniques, and whether its production provides a selective advantage on certain host genotypes.