Project Design

Fusarium head blight (FHB) is a fungal disease that decimates cereal crops by reducing seed quality and grain yields across the world. Fusarium graminearum is the leading agent of head blight in Canada, the United States, and Europe. During the 1990s, the United States alone estimated 3 billion USD in economic losses from an epidemic caused by FHB [1].

Fusarium infects grain crops during flowering and grain development [2]. The fungus produces airborne spores that land on spikelets of flowering crops such as wheat, infecting the xylem and pith tissues. These vascular bundles of the rachis allow the fungal hyphae to spread from spikelet to spikelet. Water soaking may occur at this stage, where the chlorenchyma becomes drenched and a bleached colour can be seen in the tissue, which is indicative of FHB [3]. After the initial infection trichothecene mycotoxins like deoxynivalenol (DON), a powerful inhibitor for protein synthesis, are produced [4]. Mycotoxins are difficult to destroy and exposure can inhibit processes including cell growth, nucleic acid synthesis, and cell division. If ingested, gastrointestinal problems and feed refusal in livestock will occur [5].

Fusarium are ascomycetes, producing ascopores during the process of meiosis. They are contained in tubular sacs called asci within dark flask-shaped perithecium. When the ascospores are released from a perithecia, the airborne spores become the main inoculum of FHB. Fusarium also produce asexual crescent-shaped macroconidia spores on surfaces of damp crop residue. Unlike ascospores however, macroconidia can only be dispersed to short distances [3].

Life cycle of F. graminearum [3]

References

1. McMullen, M., Jones, R., and Gallenberg, D. (1997). Scab of wheat and barley: a reemerging disease of devastating impact. Plant Disease, 81, 1340-1348
2. Del Ponte, E.M., Fernandes, J.M.C., and Bergstrom, G.C. (2007). Influence of growth stage on fusarium head blight and deoxynivalenol production in wheat. J Phytopathol, 155, 577-581.
3. Trail, F. (2009). For Blighted Waves of Grain: Fusarium graminearum in the Postgenomics Era. Plant Physiology, 149(1), 103-110.
4. Harris, L.J., Desjardins, A.E., Plattner, R.D., Nicholson, P., Butler, B., Young, J.C., Weston, G., Proctor, R.H., Hohn, T.M. (1999). Possible role of trichothecene mycotoxins in virulence of Fusarium graminearum on maize. Plant Dis, 83, 954-960.
5. Rocha, O., Ansari, K., and Doohan, F.M. (2005). Effects of trichothecene mycotoxins on eukaryotic cells: A review. Food Addit Contam, 22, 369-378.