Wheat Pore-forming toxin-like protein confers broad-spectrum resistance to fungal pathogens in Arabidopsis.

Fusarium head blight (FHB), caused by the hemibiotrophic fungus Fusarium graminearum, is one of the major threats to global wheat productivity. A wheat Pore-Forming Toxin-like (PFT) protein was previously reported to underlie Fhb1, the most widely used quantitative trait locus (QTL) in FHB breeding programs worldwide. In the present work, wheat PFT was ectopically expressed in model dicot plant Arabidopsis. The heterologous expression of wheat PFT in Arabidopsis provided a broad-spectrum quantitative resistance to fungal pathogens including, F. graminearum, Colletotrichum higginsianum, Sclerotinia sclerotiorum, and Botrytis cinerea. However, there was no resistance to bacterial or oomycete pathogens Pseudomonas syringae and Phytophthora capsici, respectively in the transgenic Arabidopsis plants. For exploring the reason for the resistance response to exclusively the fungal pathogens, purified PFT protein was hybridized to a glycan microarray having 300 different types of carbohydrate monomers and oligomers. It was found that PFT specifically hybridized with chitin monomer, N-Acetyl glucosamine (GlcNAc), which is present in fungal cell walls but not in bacteria or Oomycetes. This exclusive recognition of chitin may be responsible for the specificity of PFT-mediated resistance to fungal pathogens. Transfer of the atypical quantitative resistance of wheat PFT to a dicot system highlights its potential utility in designing broad-spectrum resistance in diverse host plants.