|WIESENBERGER, GERLINDE - University Of Natural Resources & Applied Life Sciences - Austria|
|VARGA, ELISABETH - University Of Natural Resources & Applied Life Sciences - Austria|
|FRUHMANN, PHILIPP - Vienna University Of Technology|
|STUCKLER, ROMANA - University Of Natural Resources & Applied Life Sciences - Austria|
|KRSKA, RUDOLF - University Of Natural Resources & Applied Life Sciences - Austria|
|BERTHILLER, FRANZ - University Of Natural Resources & Applied Life Sciences - Austria|
|ADAM, GERHARD - University Of Natural Resources & Applied Life Sciences - Austria|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/22/2015
Publication Date: 3/22/2015
Citation: Wiesenberger, G., Varga, E., Fruhmann, P., Stuckler, R., Ward, T.J., Krska, R., Berthiller, F., Adam, G. 2015. Biosynthesis of DON/15-ADON and NX-2 by different variants of TRI1 from Fusarium graminearum [abstract].
Technical Abstract: Fusarium graminearum is one of the econimically most important plant pathogens causing diseases such as Fusarium Head Blight (FHB) of small grain cereals and ear rot of maize. During a large scale survey of Fusarium graminearum (sensu strictu) in the northern United States strains (termed N-strains) had been discovered (Liang et al., 2014), which show normal aggressiveness and produce a novel type A trichothecene termed NX-2. This mycotoxin is identical to 3-ADON with the exception that it lacks the keto group at C-8 (Varga et al., 2014). In various Fusarium species oxidation at C-7 and C-8 of trichothecenes is performed by P450 monooxygenases encoded by TRI1 genes. We sequenced the TRI1 genes of several N strains and found 14 amino acid changes between the Tri1 proteins of PH-1 and the N-strains. By swapping the coding regions of the DON/15-ADON producing strain PH-1 and one of our N-isolates (WG-9) we confirmed, that the N-variant of the Tri1 protein is indeed responsible for the specific oxidation at the C-7 of NX-2 (Varga et al., 2104). We constructed hybrid genes to further investigate which amino acids in the Tri1 proteins account for the specific oxidation reactions. Since functional tests are tedious and time consuming when performed in Fusarium, we have set up a yeast system for investigation of the Tri1 proteins. We purified large amounts of calonectrin, which is an intermediate compound and the substrate for the Tri1 monooxygenase and plan to feed this to a newly constructed trichothecene resistant Saccharomyces cerevisiae strain expressing the TRI1 cDNAs from PH-1, WG-9 and various hybrid genes.