Identification, Molecular Cloning, and Functional Characterization of a Wheat UDP-Glucosyltransferase Involved in Resistance to Fusarium Head Blight and to Mycotoxin Accumulation

Abstract

Plant uridine diphosphate (UDP)-glucosyltransferases (UGT) catalyze the glucosylation of xenobiotic, endogenous substrates and phytotoxic agents produced by pathogens such as mycotoxins. The <i>Bradi5g03300</i> UGT-encoding gene from the model plant <i>Brachypodium distachyon</i> was previously shown to confer tolerance to the mycotoxin deoxynivalenol (DON) through glucosylation into DON 3-<i>O</i>-glucose (D3G). This gene was shown to be involved in early establishment of quantitative resistance to Fusarium Head Blight, a major disease of small-grain cereals. In the present work, using a translational biology approach, we identified and characterized a wheat candidate gene, <i>Traes_2BS_14CA35D5D</i>, orthologous to <i>Bradi5g03300</i> on the short arm of chromosome 2B of bread wheat (<i>Triticum aestivum L</i>.). We showed that this UGT-encoding gene was highly inducible upon infection by a DON-producing <i>Fusarium graminearum</i> strain while not induced upon infection by a strain unable to produce DON. Transformation of this wheat UGT-encoding gene into <i>B. distachyon</i> revealed its ability to confer FHB resistance and root tolerance to DON as well as to potentially conjugate DON into D3G <i>in planta</i> and its impact on total DON reduction. In conclusion, we provide a UGT-encoding candidate gene to include in selection process for FHB resistance.