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

Authors: SINGH, LOVEPREET - University Of Maryland; SINHA, ARUNIMA - University Of Maryland; GUPTA, MEGHA - University Of Maryland; XIAO, SHUNYUAN - University Of Maryland; Hammond, Rosemarie; RAWAT, NIDHI - University Of Maryland

Submitted to: Molecular Plant-Microbe Interactions
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/1/2023
Publication Date: 3/9/2023
Citation: Singh, L., Sinha, A., Gupta, M., Xiao, S., Hammond, R., Rawat, N. 2023. Wheat pore-forming toxin-like protein confers broad-spectrum resistance to fungal pathogens in Arabidopsis. Molecular Plant-Microbe Interactions. https://doi.org/10.1094/MPMI-12-22-0247-R.
DOI: https://doi.org/10.1094/MPMI-12-22-0247-R

Interpretive Summary: Wheat is one of the most important food crops cultivated globally. Fusarium head blight (FHB), caused by the ascomycete fungus Fusarium graminearum, is one of the most devastating diseases of wheat. Several quantitative trait loci providing resistance to FHB have been mapped in wheat and previous studies showed a pore-forming toxin-like (PFT) protein underlies the Fhb1-mediated resistance in wheat. The PFT contains a lectin-binding domain and a pore-forming domain and is an atypical resistance protein. The goal of the present work was to test if the wheat PFT-mediated resistance could be ectopically transferred to a dicot plant system, and if so, could it provide broad-spectrum resistance to several fungal, bacterial and oomycete pathogens. Although PFT imparted resistance to a wide range of economically important fungal pathogens, it did not provide resistance against bacterial or oomycete pathogens, implying a role of the lectin-binding domain in binding to and recognizing fungal pathogens. The results suggest that PFT may be transferred to a wide range of plant systems for effective resistance against a number of agriculturally important fungal pathogens and is of interest to plant breeders, growers, and plant pathologists.

Technical Abstract: 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.