Targeting fungal cell walls and metabolites to control wheat Fusarium head blight

Abstract

Fusarium head blight (FHB) is a devastating disease of wheat and other small grain cereals worldwide that is caused by toxigenic Fusarium species. Mycotoxins such as deoxynivalenol (DON) produced by FHB pathogens are secondary metabolites, highly toxic to human and domestic animals and virulent to plants. Plant germplasm resources with natural resistance against FHB are inadequate, and the breeding of resistant crop cultivars via conventional approaches has been a challenge. We have used different strategies to select non-plant-derived resources to use for FHB resistance. Animal antibodies were generated by phage display that target a highly conserved cell wall-bound protein that catalyses the production of H₂O₂ and is a virulent factor in Fusarium pathogens; the antibody-antigen recognition defines a specific interaction; Combined the pathogen-specific resistance with tissue-specific and pathogen-inducible expression conferred durable resistance to FHB and mycotoxins in wheat. Fungal RNAi sequences were identified by genetic and functional analyses that target chitin synthases in cell walls of Fusarium and provided an efficient protection of wheat under high disease pressures. Bacterial genes coding for enzymes degrading DON by targeting DON C3 group were isolated by comparative genome sequencing and heterologous expression and used to control FHB pathogens and mycotoxins. Our results indicated that non-plant-derived resources may be widely utilized in FHB resistance and mycotoxin elimination in agriculture and food/feed industries.