ARS | Publication request: Transgenic Arabidopsis thaliana expressing a barley UDP-glucosyltransferase exhibit resistance to the mycotoxin deoxynivalenol

Submitted to: Journal of Experimental Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 30, 2012
Publication Date: August 24, 2012
Citation: Shin, S., Torres-Acosta, J.A., Heinen, S.J., Mccormick, S.P., Lemmens, M., Kovalsky-Paris, P.M., Berthiller, F., Adam, G., Muehlbauer, G.J. 2012. Transgenic Arabidopsis thaliana expressing a barley UDP-glucosyltransferase exhibit resistance to the mycotoxin deoxynivalenol. Journal of Experimental Botany. 63(13):4731-4740.

Interpretive Summary: In this research we found that a barley gene may help to control Fusarium head blight (FHB). FHB, caused by the fungus Fusarium graminearum, is a devastating disease of small grain cereal crops that causes yield reductions and contamination of grain with the trichothecene mycotoxin deoxynivalenol (DON). DON is harmful to the health of humans and livestock because of its ability to block protein synthesis. It is also an important virulence factor for FHB, therefore making plants that have greater resistance to DON is a way of improving resistance to the disease. In the study, a gene from barley for an enzyme that detoxifies DON was introduced into the model plant Arabidopsis. Plants that expressed this barley gene were more resistant to DON. This barley gene is a promising candidate for transgenic approaches for improving Fusarium resistance of crop plants.

Technical Abstract: Fusarium head blight (FHB), caused by Fusarium graminearum, is a devastating disease of small grain cereal crops. FHB causes yield reductions and contamination of grain with trichothecene mycotoxins such as deoxynivalenol (DON). DON inhibits protein synthesis in eukaryotic cells and acts as a virulence factor during fungal pathogenesis, therefore resistance to DON is considered an important component of resistance against FHB. One mechanism of resistance to DON is conversion of DON to DON-3-O-glucoside (D3G). Previous studies showed that expression of the UDP-glucosyltransferase genes HvUGT13248 from barley and AtUGt73C5 (DOGT1) from Arabidopsis thaliana conferred DON resistance to yeast. Overexpression of AtUGt73C5 in Arabidopsis led to increased DON resistance of seedlings but also to dwarfing of transgenic plants due to formation of brassinosteroid-glucosides. The objective of this study was to develop transgenic Arabidopsis expressing HvUGT13248 and to test for phenotypic changes in growth habit and in the response to DON. Transgenic lines that constitutively expressed the epitope-tagged HvUGT13248 protein exhibited increased resistance to DON in a seed germination assay and converted DON to D3G to a higher extent than the untransformed wildtype. In contrast to the Arabidopsis AtUGT73C5 gene, expression of the barley HvUGT13248 gene did not lead to drastic morphological changes. Consistent with this observation, no castasterone-glucoside formation was detectable in yeast expressing the barley HvUGT13248 gene. This barley UGT is therefore a promising candidate for transgenic approaches aiming to increase DON and Fusarium resistance of crop plants without undesired collateral effects