Inhibition of germination of Orobanche ramosa seeds by Fusarium toxins. Phytoparasitica

Eighteen toxins produced by Fusarium species were tested at different concentrations on Orobanche ramosa seeds to evaluate their effectiveness in inhibiting germination. Many of them were active at the highest concentration used. Seven of them, i.e.: fusarenon X, nivalenol, deoxynivalenol, T-2 toxin, HT-2 toxin, diacetoxyscirpenol and neosolaniol were highly active at 10 µM, causing 100% inhibition of germination. Many of them were still active when assayed at a concentration ten times lower, with T-2, HT-2, nivalenol, neosolaniol and diacetoxyscirpenol being still able to cause total inhibition; the latter was very active also at 0.1µM, causing more than 90% inhibition. The results show that the use of toxic secondary metabolites could represent a useful alternative strategy in the management of parasitic weeds, interfering with the induced germination process, and that fungal culture extracts could be an interesting source of new compounds acting as natural and original herbicides.