Exploring Fusarium head blight (FHB) resistance with nanoparticles and EMS in wheat

Abstract

Fusarium head blight (FHB), a disease caused by Fusarium fungi species, affects many small grain crops. It affects crop yield, quality, and safety. Affected wheat results in losses of $5.6 billion USD per year in North America alone, and outbreaks are only predicted to increase. Developing and growing FHB resistant wheat cultivars is one of the effective approaches to minimize FHB losses. The Fhb1 and Fhb7 genes have shown marked success when it comes to Type II resistance in wheat plants. Using nanoparticles and ethyl methanesulfonate (EMS) mutations, these genes were examined in two projects. In the first project, lipid nanoparticles were paired with gene-editing plasmids with the goal of knocking out the wildtype TaHRC-S region of Fhb1 gene in Bobwhite wheat seeds. This was done by treating the shoot apical meristems (SAMs) in germinated seeds to mutate the pluripotent cells before plant growth. If successful, this would introduce persistent mutations without integrating any transgenes. While there has been previous success in a pilot study with this method, our plants did not show any mutations once sequenced. In the second project, Chinese Spring wheat seeds were randomly mutated. Lines with mutations in the Fhb7 region were isolated and the FHB resistance of these lines was assessed phenotypically. This yielded 32 lines with significant mutations. 18 of these indicated a mutation in an essential area of the Fhb7 gene that alters the resistance when compared to the wildtype. The remaining 14 lines showed signs of having significant mutations outside of the targeted region. Any synonymous mutations in the susceptible lines were set to the side, for more analysis on missense mutations in the Fhb7 region. To further connect these mutations with the phenotypic susceptibility, crown rot trials were correlated with our results. The results of this study will narrow down the essential regions in the Fhb7 gene for resistance and provided important mutant lines for further FHB research.