The cDNA encoding the antifungal protein KP4 from Ustilago maydis-infecting 
virus was inserted behind the ubiquitin promoter of maize and genetically 
transferred to wheat varieties particularly susceptible to stinking smut 
(Tilletia tritici) disease. The transgene was integrated and inherited over 
several generations. Of seven transgenic lines, three showed antifungal activity 
against U. maydis. The antifungal activity correlated with the presence of the 
KP4 transgene. KP4-transgenic, soil-grown wheat plants exhibit increased 
endogenous resistance against stinking smut.