Bilateral BBSRC-Embrapa: Using disease risk forecasting, NGS and HIGS to explore and control Fusarium Head Blight disease in wheat fields

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This is a highly innovative and truly ground breaking research project devised by scientists based at Embrapa Wheat, Soybean, Genetic Resources and Biotechnology and Bioinformatics in Brazil and Rothamsted Research in the UK. The problem to be addressed is the control of a fungal disease called Fusarium head blight (FHB) which is one of the most serious and hazardous crop diseases worldwide. The main consequence of FHB is that trichothecene mycotoxins, such as deoxynivalenol (DON), accumulate in the grain, presenting a health risk to humans and animals. In Southern Brazil, where 90% of Brazilian wheat is grown, severe FHB epidemic years occur at a minimum of every 4 or 5 years. Legal limits have been set on the DON levels permitted in harvested grain used for different purposes. However, even moderate FHB years are highly problematic causing the lack of available safe grain for use either on farms or for sale into the market. For low income Brazilian farmers, FHB disease reduces the standards of living of farmer's families and that of their local communities. There is a pressing need to develop novel and effective FHB control options.In this project, we intend to take a novel whole fungal genome and disease modelling guided approach to develop a pipeline of genetically modified wheat genotypes harbouring T-DNA constructs, which can silence Fusarium genes critical for wheat infection via host-induced gene silencing (HIGS). We also intend to determine the plant and fungal mechanisms that control the HIGS phenomenon. HIGS could be used to control multiple pathogens.This project has six main research steps.1. To explore using next generation sequencing the genomes of the five FHB causing species in Southern Brazil. Define the core and species-specific proteome of the FHB species complex (FGSC) for the development of molecular diagnostic tools and the selection of HIGS targets. Monitor for possible genome alterations over 3 years.2. To enhance FHB disease risk forecasting, by establishing a spore sampler network that can detect and quantify Fusarium species. Devise and use diagnostic assays to identify and monitor FGSC diversity. Sample atmospheric Fusarium spores to identify potential inoculum sources and population structure. Incorporate data on the dynamics of airborne Fusarium spore populations into the existing regional FHB risk model. 3. To develop various T-DNA based constructs to silence Fusarium gene expression by HIGS, thereby controlling Fusarium infections. Evaluate single gene HIGS constructs using a novel cut wheat tillers (transient assay) and via stable transformation into Arabidopsis or lettuce. Two lead HIGS constructs targeting multiple Fusarium genes will be transform into a moderately FHB resistance Brazilian wheat cultivar. In the resulting transgenic plant populations, FHB severity and DON levels will be quantified. 4. To explore the underlying mechanisms of HIGS three cutting edge experiments will be completed. We will establish if long or short RNA molecules move between fungal and wheat cells, determine if the gene silencing phenomena once initiated operates systemically and investigate if transported RNA molecules are cargoed using vesicular transport to the plant cell surface for delivery into fungal cells.5. To perform two years of GM wheat trial in two locations in Brazil using the four best HIGS lines and three appropriate control lines. Assess in-field FHB symptoms, airborne inoculum, grain quality, DON contamination and fungal spore production. To collect Fusarium isolates able to cause any disease on the HIGS lines and complete a full genome analyse.6. The research team will engage with farmers, farmer co-operatives, grain purchasers, plant breeders in Brazil and the UK and academics globally to explain the project, the research findings and discuss ways to implement the new modelling/forecasting technologies, to use the novel GM trait and further understand the HIGS phenomenon.