|Kistler, H - Corby|
Submitted to: Meeting Abstract
Publication Type: Abstract only
Publication Acceptance Date: 6/18/2014
Publication Date: 6/18/2014
Citation: Wiesenberger, G., Varga, E., Hametner, C., Stuckler, R., Kistler, H.C., Ward, T.J., Schofbeck, D., Schuhmacher, R., Berthiller, F., Adam, G. 2014. North American isolates of Fusarium graminearum produce a novel type A trichothecene [abstract]. Mycotoxin Workshop. Interpretive Summary:
Technical Abstract: Deoxynivalenol (DON) is a virulence factor of Fusarium graminearum on wheat and most likely on other host plants. A large scale survey of F. graminearum (sensu strictu) conducted in the northern United States revealed the existence of strains which - based on molecular markers - belong to the 3-acetyl-DON (3-ADON) chemotype, but do not produce DON or nivalenol or any of their known derivatives). Nevertheless we found, that these strains synthesize the trichothecene precursor trichodiene. A compound specifically occurring in these strains was purified and its structure was elucidated. The novel trichothecene, termed NX-2, 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 NX-2 is deactylated to dNX-2, like 3-ADON to DON. The toxicity of dNX-2 is very similar to that of DON in plant and animal derived in vitro translation systems. By swapping the TRI1 coding regions between the DON producing strain PH-1 and the NX-2 producing strain WG-9 we were able to show, that this variant of Tri1p is responsible for specific oxidation at C-7 of the newly discovered trichothecene. At present it is unclear, 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. This work was supported by the Special Research Program SFB Fusarium (SFB F37) from the Austrian Science Fund (FWF).