Search for host defense markers uncovers an apple agglutination factor corresponding with fire blight resistance

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 in FHB breeding programs worldwide. In the present work, wheat PFT was ectopically expressed in the model dicot plant Arabidopsis. 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. To explore 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 oomycete species. 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. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

The Use of Potassium Phosphonate (KHP) for the Control of Major Apple Pests

Phosphonate-based products have demonstrated diverse abilities to protect crops against pests, with various modes of action proposed. In this article, we specifically investigated potassium phosphonate (KHP) on apple crops. Its performance to control three major apple bioagressors (Venturia inaequalis, Erwinia amylovora, and Dysaphis plantaginea) was evaluated under semicontrolled conditions. The product was able to confer significant protection rates (40 to 75% for apple scab, 40% for fire blight, and 30% for rosy aphid), which can be explained by its more or less efficient biocidal activity against the three pests, and by its ability to induce apple immunity (pathogenesis-related proteins and secondary metabolites genes). A cumulative effect of treatments as well as the systemic behavior of the product was demonstrated. Fields trials against apple scab and the postharvest disease bull's eyes rot (Neofabraea vagabunda) were performed on different apple varieties by applying KHP combined with light pest management programs either reducing (dessert orchards) or suppressing (cider orchards) fungicide applications. KHP was able to reduce apple scab by 70 to 90% on shoots and young and harvested fruit, and bull's eyes rot by 70 to 90% on harvested fruit. Overall, our results indicate that KHP is useful for the protection of apple trees against its major pests by direct effect and by triggering the host defense system.