Investigations on the ability of FHB1 to protect wheat against nivalenol and deoxynivalenol

Our main goal in this contribution was to investigate whether Fhb1 also governs resistance towards NIV, a trichothecene structurally related to DON. Here we report preliminary results on a first series of experiments done to clarify this issue. Using mutants with a disrupted trichodiene synthase, it is confirmed that NIV and DON production are fungal virulence factors important for the spread of symptoms in the wheat ear but not for the induction of Fusarium head blight. Both toxins affect the probability that symptoms spread. It is demonstrated that NIV is phytotoxic on wheat ears and that the purified toxin can induce symptoms identical to those described for DON. Fhb1 protects the wheat line against both NIV and DON. The mechanism of NIV resistance is not known but is probably different from the detoxification mechanism of DON. We could not confirm that Fhb1 increases resistance to both NIV- and DON-producing Fusarium strains.