Antifungal activity of a Bowman-Birk-type trypsin inhibitor from wheat kernel

A trypsin inhibitor from wheat kernel (WTI) was found to have a strong anti fungal activity against a number of pathogenic fungi and to inhibit fungal trypsin-like activity. WTI inhibited in vitro spore germination and hyphal growth of pathogens, with protein concentration required for 50% growth inh ibition (IC50) values ranging from 111.7 to above 500 mu g/ml. As observed by electron microscopy, WTI determined morphological alterations represente d by hyphal growth inhibition and branching. One of the fungal species test ed, Botrytis cinerea produced a trypsin-like protease, which was inhibited by the trypsin inhibitor. WTI, as well as other seed defence proteins, appe ar to be an important resistance factor in wheat kernels during rest and ea rly germination when plants are particularly exposed to attack by potential soilborne pathogens.