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. Over-expression of AtUGt73C5 in Arabidopsis led to increased DON resistance of seedlings but also to dwarfing of transgenic plants due to the formation of brassinosteroid-glucosides. The objectives of this study were to develop transgenic Arabidopsis expressing HvUGT13248, to test for phenotypic changes in growth habit, and 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 wild-type. By contrast to the over-expression of DOGT1 in Arabidopsis, which conjugated the brassinosteriod castasterone with a glucoside group resulting in a dwarf phenotype, 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.
Bibliographical noteFunding Information:
We would like to thank Dr Fumiaki Katagiri at the University of Minnesota for providing the pMDC32 plasmid. We are indebted to Abigail Cole and Anthony Jakubiak for excellent technical assistance. This project is supported by funds from the USDA-ARS US Wheat and Barley Scab Initiative and the Minnesota Small Grains Initiative to GJM. GA, ML, and FB received funding from the Austrian Science fund (SFB Fusarium, F3701, F3706, F3708 and L475-B09) and FB from the Federal Ministry of Economy, Family, and Youth as well as from the National Foundation for Research, Technology, and Development. Sanghyun Shin was supported by a postdoctoral fellowship programme of the National Institute of Crop Science (NICS), Rural Development Administration (RDA), Republic of Korea, and a grant from the Next-Generation BioGreen21 program (No.PJ00800602), Rural Development Administration, Republic of Korea.
- Fusarium head blight