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

Miriam Gatti,Thierry Langin,Frédéric Choulet,Catherine Macadré,Marie Dufresne,Jean-Marc Seng,Florence Guérard

doi:10.3389/fpls.2018.01853

Abstract

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

Highlights

IntroductionA Wheat UGT Involved in FHB Resistance
Wheats comprising bread wheat (T. aestivum) and durum wheat (T. turgidum ssp. durum) are among the major cereals produced worldwide, presently raking second after maize as other major crops wheat is confronted to different biotic stresses during its development, inducing deteriorations in both yield and grain quality.A Wheat UGT Involved in FHB ResistanceCommon in European bread wheat varieties, Fusarium Head Blight, named wheat scab, is one of the most important diseases of cereal crops (Dweba et al, 2017)
A recent study showed that overexpression of this gene in wheat conferred quantitative type II resistance to FHB, FIGURE 5 | Traes_2BS_14CA35D5D contributes to resistance to Fg DON+ colonization in Brachypodium distachyon infected spikes

Summary

Introduction

A Wheat UGT Involved in FHB Resistance. Common in European bread wheat varieties, Fusarium Head Blight, named wheat scab, is one of the most important diseases of cereal crops (Dweba et al, 2017). DON-negative mutant strains impaired in the Tri gene coding for the trichodiene synthase, the first enzyme of the biosynthetic pathway, are unable to efficiently colonize wheat spikes (Bai et al, 2002; Jansen et al, 2005; Maier et al, 2006). One of the major quantitative trait loci in wheat is Fhb (Qfhs.ndsu3BS), involved in disease spread along the spike, referred to as type II resistance, as is the case for numerous major QTLs (Buerstmayr et al, 2009). Metabolic profiling revealed that DON can be detoxified through glucosylation and Sglutathionylation (Berthiller et al, 2009; Kluger et al, 2013, 2015; Warth et al, 2015)

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